🩹 Fix a NeoPixel override (#26492)

Author: ellensp

Marlin/src/pins/stm32f4/pins_MKS_MONSTER8_V2.h

@@ -58,6 +58,9 @@
   #define WIFI_RESET_PIN                    PD14  // MKS ESP WIFI RESET PIN
 #endif
 
-#define NEOPIXEL_PIN                        PC5
+// The FYSETC_MINI_12864_2_1 uses one of the EXP pins
+#if DISABLED(FYSETC_MINI_12864_2_1) && !defined(NEOPIXEL_PIN)
+  #define NEOPIXEL_PIN                      PC5
+#endif
 
 #include "pins_MKS_MONSTER8_common.h"