Simpler G92 for SCARA

Marlin/Marlin_main.cpp

@@ -3832,16 +3832,21 @@ inline void gcode_G92() {
 
   LOOP_XYZE(i) {
     if (code_seen(axis_codes[i])) {
+      #if IS_SCARA
+        current_position[i] = code_value_axis_units(i);
+        if (i != E_AXIS) didXYZ = true;
+      #else
         float p = current_position[i],
               v = code_value_axis_units(i);
 
         current_position[i] = v;
 
         if (i != E_AXIS) {
+          didXYZ = true;
           position_shift[i] += v - p; // Offset the coordinate space
           update_software_endstops((AxisEnum)i);
-        didXYZ = true;
         }
+      #endif
     }
   }
   if (didXYZ)