remove unused parameter VT_AIRSPD_RULE (#10897)

- fixes #10896

src/modules/fw_att_control/FixedwingAttitudeControl.cpp

@@ -119,7 +119,6 @@ FixedwingAttitudeControl::FixedwingAttitudeControl() :
 
 	// initialize to invalid VTOL type
 	_parameters.vtol_type = -1;
-	_parameters.vtol_airspeed_rule = 0;
 
 	/* fetch initial parameter values */
 	parameters_update();
@@ -241,7 +240,6 @@ FixedwingAttitudeControl::parameters_update()
 
 	if (_vehicle_status.is_vtol) {
 		param_get(_parameter_handles.vtol_type, &_parameters.vtol_type);
-		param_get(_parameter_handles.vtol_airspeed_rule, &_parameters.vtol_airspeed_rule);
 	}
 
 	param_get(_parameter_handles.bat_scale_en, &_parameters.bat_scale_en);
@@ -439,7 +437,6 @@ FixedwingAttitudeControl::vehicle_status_poll()
 				_attitude_setpoint_id = ORB_ID(fw_virtual_attitude_setpoint);
 
 				_parameter_handles.vtol_type = param_find("VT_TYPE");
-				_parameter_handles.vtol_airspeed_rule = param_find("VT_AIRSPD_RULE");
 
 				parameters_update();
 

src/modules/fw_att_control/FixedwingAttitudeControl.hpp

@@ -202,7 +202,6 @@ private:
 		float rattitude_thres;
 
 		int32_t vtol_type;			/**< VTOL type: 0 = tailsitter, 1 = tiltrotor */
-		int32_t vtol_airspeed_rule;
 
 		int32_t bat_scale_en;			/**< Battery scaling enabled */
 		bool airspeed_disabled;
@@ -272,7 +271,6 @@ private:
 		param_t rattitude_thres;
 
 		param_t vtol_type;
-		param_t vtol_airspeed_rule;
 
 		param_t bat_scale_en;
 		param_t airspeed_mode;

src/modules/vtol_att_control/vtol_att_control_params.c

@@ -314,14 +314,3 @@ PARAM_DEFINE_INT32(VT_FW_DIFTHR_EN, 0);
  * @group VTOL Attitude Control
  */
 PARAM_DEFINE_FLOAT(VT_FW_DIFTHR_SC, 0.1f);
-
-/**
- * Airspeed rules regarding fixed wing control surface scaling.
- *
- * @value 0 No special rules
- * @value 1 During hover (excluding transitions) use the lowest possible airspeed value.
- * @min 0.0
- * @increment 1
- * @group VTOL Attitude Control
- */
-PARAM_DEFINE_INT32(VT_AIRSPD_RULE, 0);