Add missing SoftwareSerial begin for TMC2208

Based on #9299

Marlin/src/HAL/HAL_AVR/SanityCheck_AVR_8_bit.h

  * TMC2208 software UART and ENDSTOP_INTERRUPTS both use pin change interrupts (PCI)
  */
 #if ENABLED(HAVE_TMC2208) && ENABLED(ENDSTOP_INTERRUPTS_FEATURE) && !( \
-       ENABLED( X_HARDWARE_SERIAL  ) \
-    || ENABLED( X2_HARDWARE_SERIAL ) \
-    || ENABLED( Y_HARDWARE_SERIAL  ) \
-    || ENABLED( Y2_HARDWARE_SERIAL ) \
-    || ENABLED( Z_HARDWARE_SERIAL  ) \
-    || ENABLED( Z2_HARDWARE_SERIAL ) \
-    || ENABLED( E0_HARDWARE_SERIAL ) \
-    || ENABLED( E1_HARDWARE_SERIAL ) \
-    || ENABLED( E2_HARDWARE_SERIAL ) \
-    || ENABLED( E3_HARDWARE_SERIAL ) \
-    || ENABLED( E4_HARDWARE_SERIAL ) )
+       defined(X_HARDWARE_SERIAL ) \
+    || defined(X2_HARDWARE_SERIAL) \
+    || defined(Y_HARDWARE_SERIAL ) \
+    || defined(Y2_HARDWARE_SERIAL) \
+    || defined(Z_HARDWARE_SERIAL ) \
+    || defined(Z2_HARDWARE_SERIAL) \
+    || defined(E0_HARDWARE_SERIAL) \
+    || defined(E1_HARDWARE_SERIAL) \
+    || defined(E2_HARDWARE_SERIAL) \
+    || defined(E3_HARDWARE_SERIAL) \
+    || defined(E4_HARDWARE_SERIAL) )
   #error "select hardware UART for TMC2208 to use both TMC2208 and ENDSTOP_INTERRUPTS_FEATURE."
 #endif
 

Marlin/src/inc/Conditionals_post.h

     #endif
   #endif
 #endif
-  
+
 // Nozzle park
 #if ENABLED(NOZZLE_PARK_FEATURE) && ENABLED(DELTA)
   #undef NOZZLE_PARK_Z_FEEDRATE

Marlin/src/module/stepper_indirection.cpp

   #include "planner.h"
 
   #define _TMC2208_DEFINE_HARDWARE(ST) TMC2208Stepper stepper##ST(&ST##_HARDWARE_SERIAL)
-  #define _TMC2208_DEFINE_SOFTWARE(ST) SoftwareSerial stepper##ST##_serial = SoftwareSerial(ST##_SERIAL_RX_PIN, ST##_SERIAL_TX_PIN); \
+  #define _TMC2208_DEFINE_SOFTWARE(ST) SoftwareSerial ST##_HARDWARE_SERIAL = SoftwareSerial(ST##_SERIAL_RX_PIN, ST##_SERIAL_TX_PIN); \
                                        TMC2208Stepper stepper##ST(&stepper##ST##_serial, ST##_SERIAL_RX_PIN > -1)
 
   // Stepper objects of TMC2208 steppers used
   #if ENABLED(X_IS_TMC2208)
-    #if defined(X_HARDWARE_SERIAL)
+    #ifdef X_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(X);
     #else
       _TMC2208_DEFINE_SOFTWARE(X);
     #endif
   #endif
   #if ENABLED(X2_IS_TMC2208)
-    #if defined(X2_HARDWARE_SERIAL)
+    #ifdef X2_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(X2);
     #else
       _TMC2208_DEFINE_SOFTWARE(X2);
     #endif
   #endif
   #if ENABLED(Y_IS_TMC2208)
-    #if defined(Y_HARDWARE_SERIAL)
+    #ifdef Y_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(Y);
     #else
       _TMC2208_DEFINE_SOFTWARE(Y);
     #endif
   #endif
   #if ENABLED(Y2_IS_TMC2208)
-    #if defined(Y2_HARDWARE_SERIAL)
+    #ifdef Y2_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(Y2);
     #else
       _TMC2208_DEFINE_SOFTWARE(Y2);
     #endif
   #endif
   #if ENABLED(Z_IS_TMC2208)
-    #if defined(Z_HARDWARE_SERIAL)
+    #ifdef Z_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(Z);
     #else
       _TMC2208_DEFINE_SOFTWARE(Z);
     #endif
   #endif
   #if ENABLED(Z2_IS_TMC2208)
-    #if defined(Z2_HARDWARE_SERIAL)
+    #ifdef Z2_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(Z2);
     #else
       _TMC2208_DEFINE_SOFTWARE(Z2);
     #endif
   #endif
   #if ENABLED(E0_IS_TMC2208)
-    #if defined(E0_HARDWARE_SERIAL)
+    #ifdef E0_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(E0);
     #else
       _TMC2208_DEFINE_SOFTWARE(E0);
     #endif
   #endif
   #if ENABLED(E1_IS_TMC2208)
-    #if defined(E1_HARDWARE_SERIAL)
+    #ifdef E1_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(E1);
     #else
       _TMC2208_DEFINE_SOFTWARE(E1);
     #endif
   #endif
   #if ENABLED(E2_IS_TMC2208)
-    #if defined(E2_HARDWARE_SERIAL)
+    #ifdef E2_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(E2);
     #else
       _TMC2208_DEFINE_SOFTWARE(E2);
     #endif
   #endif
   #if ENABLED(E3_IS_TMC2208)
-    #if defined(E3_HARDWARE_SERIAL)
+    #ifdef E3_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(E3);
     #else
       _TMC2208_DEFINE_SOFTWARE(E3);
     #endif
   #endif
   #if ENABLED(E4_IS_TMC2208)
-    #if defined(E4_HARDWARE_SERIAL)
+    #ifdef E4_HARDWARE_SERIAL
       _TMC2208_DEFINE_HARDWARE(E4);
     #else
       _TMC2208_DEFINE_SOFTWARE(E4);
   #endif
 
   void tmc2208_serial_begin() {
-    #if ENABLED(X_IS_TMC2208) && defined(X_HARDWARE_SERIAL)
-      X_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(X_IS_TMC2208)
+      X_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(X2_IS_TMC2208) && defined(X2_HARDWARE_SERIAL)
-      X2_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(X2_IS_TMC2208)
+      X2_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(Y_IS_TMC2208) && defined(Y_HARDWARE_SERIAL)
-      Y_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(Y_IS_TMC2208)
+      Y_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(Y2_IS_TMC2208) && defined(Y2_HARDWARE_SERIAL)
-      Y2_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(Y2_IS_TMC2208)
+      Y2_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(Z_IS_TMC2208) && defined(Z_HARDWARE_SERIAL)
-      Z_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(Z_IS_TMC2208)
+      Z_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(Z2_IS_TMC2208) && defined(Z2_HARDWARE_SERIAL)
-      Z2_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(Z2_IS_TMC2208)
+      Z2_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(E0_IS_TMC2208) && defined(E0_HARDWARE_SERIAL)
-      E0_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(E0_IS_TMC2208)
+      E0_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(E1_IS_TMC2208) && defined(E1_HARDWARE_SERIAL)
-      E1_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(E1_IS_TMC2208)
+      E1_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(E2_IS_TMC2208) && defined(E2_HARDWARE_SERIAL)
-      E2_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(E2_IS_TMC2208)
+      E2_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(E3_IS_TMC2208) && defined(E3_HARDWARE_SERIAL)
-      E3_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(E3_IS_TMC2208)
+      E3_HARDWARE_SERIAL.begin(115200);
     #endif
-    #if ENABLED(E4_IS_TMC2208) && defined(E4_HARDWARE_SERIAL)
-      E4_HARDWARE_SERIAL.begin(250000);
+    #if ENABLED(E4_IS_TMC2208)
+      E4_HARDWARE_SERIAL.begin(115200);
     #endif
   }
 
   }
 #endif // HAVE_TMC2208
 
-
 //
 // L6470 Driver objects and inits
 //