Fix compilation error when PIDTEMP is undefined and ULTIPANEL is defined.

Marlin/ultralcd.pde

         }
         
       }break;
+      	#ifdef PIDTEMP
       case ItemCT_PID_P: 
       {
       if(force_lcd_update)
         }
         
       }
+      	#endif
       #endif
       break;
     default: