Update ubl_motion.cpp

Restore necessary and needed loop termination logic.

Marlin/src/feature/bedlevel/ubl/ubl_motion.cpp

         xi_cnt--;
       }
 
-      //if (xi_cnt < 0 || yi_cnt < 0) break; // Too far! Exit the loop and go to FINAL_MOVE
+      if (xi_cnt < 0 || yi_cnt < 0) break; // Too far! Exit the loop and go to FINAL_MOVE
     }
 
     if (g26_debug_flag)