Allow Z_STOP_PIN override on SKR 1.4 (#17063)

Marlin/src/pins/lpc1768/pins_BTT_SKR_V1_4.h

@@ -79,14 +79,20 @@
     #define Z_MIN_PIN      P1_00   // PWRDET
   #endif
 #else
+  #ifndef Z_STOP_PIN
     #define Z_STOP_PIN     P1_27   // Z-STOP
+  #endif
 #endif
 
 //
 // Z Probe (when not Z_MIN_PIN)
 //
 #ifndef Z_MIN_PROBE_PIN
+  #if Z_STOP_PIN != P1_27
+    #define Z_MIN_PROBE_PIN P1_27
+  #else
     #define Z_MIN_PROBE_PIN P0_10
+  #endif
 #endif
 
 //