Move M250 to cpp

Marlin/src/Marlin.cpp

   return false;
 }
 
-#if HAS_LCD_CONTRAST
-  #include "gcode/lcd/M250.h"
-#endif
-
 #if ENABLED(PREVENT_COLD_EXTRUSION)
   #include "gcode/config/M302.h"
 #endif

Marlin/src/gcode/gcode.cpp

 extern void gcode_M163();
 extern void gcode_M164();
 extern void gcode_M165();
-extern void gcode_M250();
 extern void gcode_M302();
 extern void gcode_M350();
 extern void gcode_M351();
       #endif
 
       #if HAS_LCD_CONTRAST
-        case 250: // M250: Set LCD contrast
-          gcode_M250();
-          break;
-      #endif // HAS_LCD_CONTRAST
+        case 250: M250(); break;  // M250: Set LCD contrast
+      #endif
 
       #if ENABLED(EXPERIMENTAL_I2CBUS)
         case 260: M260(); break;  // M260: Send data to an i2c slave

Marlin/src/gcode/lcd/M250.h → Marlin/src/gcode/lcd/M250.cpp

  *
  */
 
+#include "../../inc/MarlinConfig.h"
+
+#if HAS_LCD_CONTRAST
+
+#include "../gcode.h"
+#include "../../lcd/ultralcd.h"
+
 /**
  * M250: Read and optionally set the LCD contrast
  */
-void gcode_M250() {
+void GcodeSuite::M250() {
   if (parser.seen('C')) set_lcd_contrast(parser.value_int());
   SERIAL_PROTOCOLPGM("lcd contrast value: ");
   SERIAL_PROTOCOL(lcd_contrast);
   SERIAL_EOL();
 }
+
+#endif // HAS_LCD_CONTRAST