FixedwingPositionControl: Only warn user when roll is reduced for a longer period of time

src/modules/fw_pos_control/FixedwingPositionControl.hpp

@@ -414,6 +414,8 @@ private:
 	// nonlinear path following guidance - lateral-directional position control
 	NPFG _npfg;
 	bool _need_report_npfg_uncertain_condition{false}; ///< boolean if reporting of uncertain npfg output condition is needed
+	hrt_abstime _time_since_first_reduced_roll{0U}; ///< absolute time since start when entering reduced roll angle for the first time
+	hrt_abstime _time_since_last_npfg_call{0U}; 	///< absolute time since start when the npfg reduced roll angle calculations was last performed
 
 	PerformanceModel _performance_model;