FW Position Control: re-add wrongly removed airspeed_poll()

Signed-off-by: Silvan Fuhrer <silvan@auterion.com>

src/modules/fw_pos_control_l1/FixedwingPositionControl.cpp

@@ -1682,6 +1682,7 @@ FixedwingPositionControl::Run()
 			_min_current_sp_distance_xy = FLT_MAX;
 		}
 
+		airspeed_poll();
 		manual_control_setpoint_poll();
 		vehicle_attitude_poll();
 		vehicle_command_poll();