Add a ZERO macro to clear arrays

Marlin/Marlin_main.cpp

@@ -3145,7 +3145,7 @@ inline void gcode_G4() {
       if (DEBUGGING(LEVELING)) DEBUG_POS(">>> home_delta", current_position);
     #endif
     // Init the current position of all carriages to 0,0,0
-    memset(current_position, 0, sizeof(current_position));
+    ZERO(current_position);
     sync_plan_position();
 
     // Move all carriages together linearly until an endstop is hit.