More universal Formbot pins

Replace `ROXYs_TRex` with pre-defines of the relevant pins at the configuration level.

Marlin/src/pins/pins_FORMBOT_RAPTOR.h

 // Formbot only supports REPRAP_DISCOUNT_SMART_CONTROLLER
 //
 #if ENABLED(REPRAP_DISCOUNT_SMART_CONTROLLER)
-  #define LCD_PINS_RS      16
-  #define LCD_PINS_ENABLE  17
-  #define LCD_PINS_D4      23
-  #define LCD_PINS_D5      25
-  #define LCD_PINS_D6      27
-  #define LCD_PINS_D7      29
   #define BEEPER_PIN       37
   #define BTN_EN1          31
   #define BTN_EN2          33
   #define BTN_ENC          35
   #define SD_DETECT_PIN    49
   #define KILL_PIN         41
+  #define LCD_PINS_RS      16
+  #define LCD_PINS_ENABLE  17
+  #define LCD_PINS_D4      23
+  #define LCD_PINS_D5      25
+  #define LCD_PINS_D6      27
+  #define LCD_PINS_D7      29
 #endif

Marlin/src/pins/pins_FORMBOT_TREX2PLUS.h

 //
 // Misc. Functions
 //
-#define CASE_LIGHT_PIN      8
 #define SDSS               53
-#ifndef ROXYs_TRex
+#ifndef LED_PIN
   #define LED_PIN          13   // The Formbot v 1 board has almost no unassigned pins on it.  The Board's LED
 #endif                          // is a good place to get a signal to control the Max7219 LED Matrix.
 
   #define PS_ON_PIN        12
 #endif
 
+#define CASE_LIGHT_PIN      8
+
 //
 // LCD / Controller
 //
 // Formbot only supports REPRAP_DISCOUNT_SMART_CONTROLLER
 //
 #if ENABLED(REPRAP_DISCOUNT_SMART_CONTROLLER)
-  #define LCD_PINS_RS      16
-  #define LCD_PINS_ENABLE  17
-  #define LCD_PINS_D4      23
-  #define LCD_PINS_D5      25
-  #define LCD_PINS_D6      27
-  #define LCD_PINS_D7      29
+  #ifndef BEEPER_PIN
+    #define BEEPER_PIN     37
+  #endif
   #define BTN_EN1          31
   #define BTN_EN2          33
   #define BTN_ENC          35
   #define SD_DETECT_PIN    49
-  #ifndef ROXYs_TRex
+  #ifndef KILL_PIN
     #define KILL_PIN       41
-    #define BEEPER_PIN     37
   #endif
+  #define LCD_PINS_RS      16
+  #define LCD_PINS_ENABLE  17
+  #define LCD_PINS_D4      23
+  #define LCD_PINS_D5      25
+  #define LCD_PINS_D6      27
+  #define LCD_PINS_D7      29
 #endif

Marlin/src/pins/pins_FORMBOT_TREX3.h

 //
 #define CASE_LIGHT_PIN      5
 #define SDSS               53
-#ifndef ROXYs_TRex
+#ifndef LED_PIN
   #define LED_PIN          13
 #endif
 
   #define BTN_EN2          33
   #define BTN_ENC          35
   #define SD_DETECT_PIN    49
-  #ifndef ROXYs_TRex
+  #ifndef KILL_PIN
     #define KILL_PIN       41
+  #endif
+  #ifndef BEEPER_PIN
     #define BEEPER_PIN     37
   #endif
 #endif

Marlin/src/pins/pins_GEN7_13.h

  * Gen7 v1.3 pin assignments
  */
 
- /**
+/**
  * Rev B    26 DEC 2016
  *
  * added pointer to a current Arduino IDE extension

config/examples/Formbot/T_Rex_2+/Configuration.h

 
 // Allow servo angle to be edited and saved to EEPROM
 //#define EDITABLE_SERVO_ANGLES
+
+#ifdef ROXYs_TRex
+  #define LED_PIN     -1
+  #define BEEPER_PIN  -1
+  #define KILL_PIN    -1
+#endif

config/examples/Formbot/T_Rex_3/Configuration.h

 
 // Allow servo angle to be edited and saved to EEPROM
 //#define EDITABLE_SERVO_ANGLES
+
+#ifdef ROXYs_TRex
+  #define LED_PIN     -1
+  #define BEEPER_PIN  -1
+  #define KILL_PIN    -1
+#endif