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_3DRAG.h

@@ -4,10 +4,8 @@
 
 #include "pins_RAMPS_13.h"
 
-#define X_MAX_PIN           -1   //2 //Max endstops default to disabled "-1", set to commented value to enable.
-
-#define Y_MAX_PIN          -1   //15
-
+#define X_MAX_PIN          2
+#define Y_MAX_PIN          15
 #define Z_MAX_PIN          -1
 
 #define SDSS               25//53

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

Marlin/pins_LEAPFROG.h

@@ -10,13 +10,13 @@
 #define X_DIR_PIN          63
 #define X_ENABLE_PIN       29
 #define X_MIN_PIN          47
-#define X_MAX_PIN          -1   //2 //Max endstops default to disabled "-1", set to commented value to enable.
+#define X_MAX_PIN          2 //Max endstops default to disabled "-1", set to commented value to enable.
 
 #define Y_STEP_PIN         14 // A6
 #define Y_DIR_PIN          15 // A0
 #define Y_ENABLE_PIN       39
 #define Y_MIN_PIN          48
-#define Y_MAX_PIN          -1   //15
+#define Y_MAX_PIN          15
 
 #define Z_STEP_PIN         31 // A2
 #define Z_DIR_PIN          32 // A6

Marlin/pins_MEGATRONICS_1.h

@@ -12,13 +12,13 @@
 #define X_DIR_PIN 47
 #define X_ENABLE_PIN 49
 #define X_MIN_PIN 5
-#define X_MAX_PIN -1 // 2 // Max endstops default to disabled "-1", set to commented value to enable.
+#define X_MAX_PIN 2
 
 #define Y_STEP_PIN 39 // A6
 #define Y_DIR_PIN 40 // A0
 #define Y_ENABLE_PIN 38
 #define Y_MIN_PIN 2
-#define Y_MAX_PIN -1 // 15
+#define Y_MAX_PIN 15
 
 #define Z_STEP_PIN 42 // A2
 #define Z_DIR_PIN 43 // A6

Marlin/pins_MEGATRONICS_2.h

@@ -12,13 +12,13 @@
 #define X_DIR_PIN 27
 #define X_ENABLE_PIN 25
 #define X_MIN_PIN 37
-#define X_MAX_PIN 40 //2 //Max endstops default to disabled "-1", set to commented value to enable.
+#define X_MAX_PIN 40
 
 #define Y_STEP_PIN 4 // A6
 #define Y_DIR_PIN 54 // A0
 #define Y_ENABLE_PIN 5
 #define Y_MIN_PIN 41
-#define Y_MAX_PIN 38 //15
+#define Y_MAX_PIN 38
 
 #define Z_STEP_PIN 56 // A2
 #define Z_DIR_PIN 60 // A6

Marlin/pins_RAMPS_OLD.h

@@ -13,19 +13,19 @@
 #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