mc_pos_control: only swithc to velocity control from hold_engaged when user moves stick

src/modules/mc_pos_control/mc_pos_control_params.c

@@ -413,6 +413,18 @@ PARAM_DEFINE_FLOAT(MPC_MAN_Y_MAX, 200.0f);
  */
 PARAM_DEFINE_FLOAT(MPC_HOLD_XY_DZ, 0.1f);
 
+
+/**
+ * Deadzone of Z stick where altitude hold is enabled
+ *
+ * @min 0.0
+ * @max 1.0
+ * @decimal 2
+ * @group Multicopter Position Control
+ */
+PARAM_DEFINE_FLOAT(MPC_HOLD_Z_DZ, 0.1f);
+
+
 /**
  * Maximum horizontal velocity for which position hold is enabled (use 0 to disable check)
  *