Fix caselight compile issues

Marlin/Marlin_main.cpp

   #ifndef INVERT_CASE_LIGHT
     #define INVERT_CASE_LIGHT false
   #endif
-  int case_light_brightness;  // LCD routine wants INT
+  uint8_t case_light_brightness;  // LCD routine wants INT
   bool case_light_on;
 
   void update_case_light() {
     pinMode(CASE_LIGHT_PIN, OUTPUT); // digitalWrite doesn't set the port mode
-    uint8_t case_light_bright = (uint8_t)case_light_brightness;
     if (case_light_on) {
       if (USEABLE_HARDWARE_PWM(CASE_LIGHT_PIN)) {
-        analogWrite(CASE_LIGHT_PIN, INVERT_CASE_LIGHT ? 255 - case_light_brightness : case_light_brightness );
+        analogWrite(CASE_LIGHT_PIN, INVERT_CASE_LIGHT ? 255 - case_light_brightness : case_light_brightness);
       }
       else WRITE(CASE_LIGHT_PIN, INVERT_CASE_LIGHT ? LOW : HIGH);
     }
     }
     else {
       if (!USEABLE_HARDWARE_PWM(CASE_LIGHT_PIN)) SERIAL_ECHOLN("Case light: on");
-      else SERIAL_ECHOLNPAIR("Case light: ", case_light_brightness);
+      else SERIAL_ECHOLNPAIR("Case light: ", (int)case_light_brightness);
     }
 
   #else

Marlin/ultralcd.cpp

 
   #if ENABLED(MENU_ITEM_CASE_LIGHT)
 
-    extern int case_light_brightness;
+    extern uint8_t case_light_brightness;
     extern bool case_light_on;
     extern void update_case_light();
 
       // ^ Main
       //
       MENU_BACK(MSG_MAIN);
-      MENU_ITEM_EDIT_CALLBACK(int3, MSG_CASE_LIGHT_BRIGHTNESS, &case_light_brightness, 0, 255, update_case_light, true);
+      MENU_ITEM_EDIT_CALLBACK(int8, MSG_CASE_LIGHT_BRIGHTNESS, &case_light_brightness, 0, 255, update_case_light, true);
       MENU_ITEM_EDIT_CALLBACK(bool, MSG_CASE_LIGHT, (bool*)&case_light_on, update_case_light);
       END_MENU();
     }