Fix build for non-sled bed auto levelling

This function should only be used with sled, not all bed auto
levelling.

Marlin/Marlin_main.cpp

   } //retract
 #endif //FWRETRACT
 
-#ifdef ENABLE_AUTO_BED_LEVELING
+#ifdef Z_PROBE_SLED
 //
 // Method to dock/undock a sled designed by Charles Bell.
 //