🐛 Fix Robin Nano v3 filament runout pins (#23344)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/pins/mega/pins_OVERLORD.h

@@ -49,7 +49,7 @@
   #define Z_MIN_PROBE_PIN                     46  // JP4, Tfeed1
 #endif
 
-#if ENABLED(FILAMENT_RUNOUT_SENSOR)
+#ifndef FIL_RUNOUT_PIN
   #define FIL_RUNOUT_PIN                      44  // JP3, Tfeed2
 #endif
 

Marlin/src/pins/pins_postprocess.h

@@ -546,14 +546,17 @@
   #undef K_MAX_PIN
 #endif
 
-// Filament Sensor first pin alias
 #if HAS_FILAMENT_SENSOR
-  #define FIL_RUNOUT1_PIN FIL_RUNOUT_PIN
+  #define FIL_RUNOUT1_PIN FIL_RUNOUT_PIN  // Filament Sensor first pin alias
 #else
   #undef FIL_RUNOUT_PIN
   #undef FIL_RUNOUT1_PIN
 #endif
 
+#if NUM_RUNOUT_SENSORS < 2
+  #undef FIL_RUNOUT2_PIN
+#endif
+
 #ifndef LCD_PINS_D4
   #define LCD_PINS_D4 -1
 #endif

Marlin/src/pins/ramps/pins_FORMBOT_TREX3.h

@@ -134,7 +134,6 @@
 #define FAN_PIN                                9
 #define FAN1_PIN                              12
 
-#define NUM_RUNOUT_SENSORS                     2
 #define FIL_RUNOUT_PIN                        22
 #define FIL_RUNOUT2_PIN                       21
 

Marlin/src/pins/sam/pins_RURAMPS4D_11.h

@@ -121,10 +121,8 @@
   #define Z_MIN_PROBE_PIN                     49
 #endif
 
-#if HAS_FILAMENT_SENSOR
-  #ifndef FIL_RUNOUT_PIN
-    #define FIL_RUNOUT_PIN             Y_MIN_PIN
-  #endif
+#ifndef FIL_RUNOUT_PIN
+  #define FIL_RUNOUT_PIN               Y_MIN_PIN
 #endif
 
 //

Marlin/src/pins/sam/pins_RURAMPS4D_13.h

@@ -109,10 +109,8 @@
   #define Z_MIN_PROBE_PIN                     49
 #endif
 
-#if HAS_FILAMENT_SENSOR
-  #ifndef FIL_RUNOUT_PIN
-    #define FIL_RUNOUT_PIN             Y_MIN_PIN
-  #endif
+#ifndef FIL_RUNOUT_PIN
+  #define FIL_RUNOUT_PIN               Y_MIN_PIN
 #endif
 
 //

Marlin/src/pins/sanguino/pins_MELZI_CREALITY.h

@@ -68,7 +68,7 @@
   #if SERVO0_PIN == BEEPER_PIN
     #undef BEEPER_PIN
   #endif
-#elif ENABLED(FILAMENT_RUNOUT_SENSOR)
+#elif HAS_FILAMENT_SENSOR
   #ifndef FIL_RUNOUT_PIN
     #define FIL_RUNOUT_PIN                    27
   #endif

Marlin/src/pins/stm32f4/pins_MKS_ROBIN_NANO_V3_common.h

@@ -145,10 +145,10 @@
 #endif
 
 #ifndef FIL_RUNOUT_PIN
-  #define FIL_RUNOUT_PIN            MT_DET_1_PIN
+  #define FIL_RUNOUT_PIN                    PA4
 #endif
 #ifndef FIL_RUNOUT2_PIN
-  #define FIL_RUNOUT2_PIN           MT_DET_2_PIN
+  #define FIL_RUNOUT2_PIN                   PE6
 #endif
 
 #ifndef POWER_LOSS_PIN