use minimal pitch field introduced in b7652986d9 for fw takeoff

src/modules/fw_pos_control_l1/fw_pos_control_l1_main.cpp

@@ -961,7 +961,7 @@ FixedwingPositionControl::control_position(const math::Vector2f &current_positio
 				/* enforce a minimum of 10 degrees pitch up on takeoff, or take parameter */
 				_tecs.update_pitch_throttle(_R_nb, _att.pitch, _global_pos.alt, _mission_item_triplet.current.altitude, calculate_target_airspeed(1.3f * _parameters.airspeed_min),
 							    _airspeed.indicated_airspeed_m_s, eas2tas,
-							    true, math::max(math::radians(mission_item_triplet.current.radius), math::radians(10.0f)),
+							    true, math::max(math::radians(mission_item_triplet.current.pitch_min), math::radians(10.0f)),
 							    _parameters.throttle_min, _parameters.throttle_max, _parameters.throttle_cruise,
 							    math::radians(_parameters.pitch_limit_min), math::radians(_parameters.pitch_limit_max));