Max endstop pins disabled by configuration

There’s no need to ask users to uncomment Max Endstop pins when they
have them. These will be set to -1 later if the endstop option is
disabled.

Marlin/pins_ELEFU_3.h

@@ -10,19 +10,19 @@
 #define X_DIR_PIN          13
 #define X_ENABLE_PIN       48
 #define X_MIN_PIN          35
-#define X_MAX_PIN          -1 //34
+#define X_MAX_PIN          34
 
 #define Y_STEP_PIN         11
 #define Y_DIR_PIN          9
 #define Y_ENABLE_PIN       12
 #define Y_MIN_PIN          33
-#define Y_MAX_PIN          -1 //32
+#define Y_MAX_PIN          32
 
 #define Z_STEP_PIN         7
 #define Z_DIR_PIN          6
 #define Z_ENABLE_PIN       8
 #define Z_MIN_PIN          31
-#define Z_MAX_PIN          -1 //30
+#define Z_MAX_PIN          30
 
 #define E2_STEP_PIN        43
 #define E2_DIR_PIN         47