Using SET_INPUT instead of pinMode

Marlin/ultralcd.cpp

     #endif
 
     #ifdef RIGIDBOT_PANEL
-      pinMode(BTN_UP,INPUT);
-      pinMode(BTN_DWN,INPUT);
-      pinMode(BTN_LFT,INPUT);
-      pinMode(BTN_RT,INPUT);
+      SET_INPUT(BTN_UP);
+      SET_INPUT(BTN_DWN);
+      SET_INPUT(BTN_LFT);
+      SET_INPUT(BTN_RT);
     #endif
 
   #else  // Not NEWPANEL