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_RAMPS_OLD.h

@@ -13,23 +13,23 @@
 #define X_DIR_PIN          28
 #define X_ENABLE_PIN       24
 #define X_MIN_PIN           3
-#define X_MAX_PIN          -1    //2
+#define X_MAX_PIN           2
 
 #define Y_STEP_PIN         38
 #define Y_DIR_PIN          40
 #define Y_ENABLE_PIN       36
 #define Y_MIN_PIN          16
-#define Y_MAX_PIN          -1    //17
+#define Y_MAX_PIN          17
 
 #define Z_STEP_PIN         44
 #define Z_DIR_PIN          46
 #define Z_ENABLE_PIN       42
 #define Z_MIN_PIN          18
-#define Z_MAX_PIN          -1    //19
+#define Z_MAX_PIN          19
 
-#define E0_STEP_PIN         32
-#define E0_DIR_PIN          34
-#define E0_ENABLE_PIN       30
+#define E0_STEP_PIN        32
+#define E0_DIR_PIN         34
+#define E0_ENABLE_PIN      30
 
 #define SDPOWER            48
 #define SDSS               53