Move M206 to cpp

Marlin/src/Marlin.cpp

   return false;
 }
 
-#if HAS_M206_COMMAND
-  #include "gcode/geometry/M206.h"
-#endif
-
 #if IS_KINEMATIC
   #include "gcode/calibrate/M665.h"
 #endif

Marlin/src/gcode/gcode.cpp

 extern void gcode_M163();
 extern void gcode_M164();
 extern void gcode_M165();
-extern void gcode_M206();
 extern void gcode_M211();
 extern void gcode_M220();
 extern void gcode_M226();
       case 205: M205(); break;    // M205: Set advanced settings
 
       #if HAS_M206_COMMAND
-        case 206: // M206: Set home offsets
-          gcode_M206();
-          break;
+        case 206: M206(); break;  // M206: Set home offsets
       #endif
 
       #if ENABLED(DELTA)

Marlin/src/gcode/geometry/M206.h → Marlin/src/gcode/geometry/M206.cpp

  *
  */
 
+#include "../../inc/MarlinConfig.h"
+
+#if HAS_M206_COMMAND
+
+#include "../gcode.h"
+#include "../../module/motion.h"
+
 /**
  * M206: Set Additional Homing Offset (X Y Z). SCARA aliases T=X, P=Y
  *
  * ***              M206 for SCARA will remain enabled in 1.1.x for compatibility.
  * ***              In the 2.0 release, it will simply be disabled by default.
  */
-void gcode_M206() {
+void GcodeSuite::M206() {
   LOOP_XYZ(i)
     if (parser.seen(axis_codes[i]))
       set_home_offset((AxisEnum)i, parser.value_linear_units());
   SYNC_PLAN_POSITION_KINEMATIC();
   report_current_position();
 }
+
+#endif // HAS_M206_COMMAND