stepper_enable: Move motor_off() logic to stepper_enable.py

Directly disable all the stepper motors on a global motor_off() from
the StepperEnable() class in stepper_enable.py.  This simplifies the
toolhead and kinematic classes.

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

klippy/kinematics/cartesian.py

@@ -17,6 +17,8 @@ class CartKinematics:
         for s in self.get_steppers():
             s.set_trapq(toolhead.get_trapq())
             toolhead.register_step_generator(s.generate_steps)
+        self.printer.register_event_handler("stepper_enable:motor_off",
+                                            self._motor_off)
         # Setup boundary checks
         max_velocity, max_accel = toolhead.get_max_velocity()
         self.max_z_velocity = config.getfloat(
@@ -84,12 +86,8 @@ class CartKinematics:
                 self._activate_carriage(altc)
             else:
                 self._home_axis(homing_state, axis, self.rails[axis])
-    def motor_off(self, print_time):
+    def _motor_off(self, print_time):
         self.limits = [(1.0, -1.0)] * 3
-        for rail in self.rails:
-            rail.motor_enable(print_time, 0)
-        for rail in self.dual_carriage_rails:
-            rail.motor_enable(print_time, 0)
     def _check_endstops(self, move):
         end_pos = move.end_pos
         for i in (0, 1, 2):
@@ -131,7 +129,6 @@ class CartKinematics:
         toolhead.set_position(self.calc_position() + [extruder_pos])
         if self.limits[dc_axis][0] <= self.limits[dc_axis][1]:
             self.limits[dc_axis] = dc_rail.get_range()
-        self.need_motor_enable = True
     cmd_SET_DUAL_CARRIAGE_help = "Set which carriage is active"
     def cmd_SET_DUAL_CARRIAGE(self, params):
         gcode = self.printer.lookup_object('gcode')