Move Stepper::synchronize to Planner (#10713)

Co-Authored-By: ejtagle <ejtagle@hotmail.com>

Marlin/src/gcode/feature/advance/M900.cpp

@@ -37,7 +37,7 @@ void GcodeSuite::M900() {
   if (parser.seenval('K')) {
     const float newK = parser.floatval('K');
     if (WITHIN(newK, 0, 10)) {
-      stepper.synchronize();
+      planner.synchronize();
       planner.extruder_advance_K = newK;
     }
     else