force_move: Use strings for axes to clear in clear_homing_state()

Pass a string such as "xyz" to kin.clear_homing_state().  This makes
the parameter a little less cryptic.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

klippy/kinematics/none.py

@@ -13,7 +13,7 @@ class NoneKinematics:
         return [0, 0, 0]
     def set_position(self, newpos, homing_axes):
         pass
-    def clear_homing_state(self, axes):
+    def clear_homing_state(self, clear_axes):
         pass
     def home(self, homing_state):
         pass