Update FYSETC AIO II TMC UART pins (#18749)

Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h

 #define E0_DIR_PIN                          PC14
 #define E0_ENABLE_PIN                       PC13
 
-#if HAS_TMC220x
+#if HAS_TMC_UART
 
   /**
    * TMC2208/TMC2209 stepper drivers
   #define Y_HARDWARE_SERIAL  Serial1
   #define Z_HARDWARE_SERIAL  Serial1
   #define E0_HARDWARE_SERIAL Serial1
-  #define TMC_SERIAL_MULTIPLEXER
-  #define SERIAL_MUL_PIN1                   PB13
-  #define SERIAL_MUL_PIN2                   PB12
+
+  // The 4xTMC2209 module doesn't have a serial multiplexer and
+  // needs to set *_SLAVE_ADDRESS in Configuration_adv.h for X,Y,Z,E0
+  #if HAS_DRIVER(TMC2208)
+    #define TMC_SERIAL_MULTIPLEXER
+    #define SERIAL_MUL_PIN1                 PB13
+    #define SERIAL_MUL_PIN2                 PB12
+  #endif
 
 #endif