chore(navigator): remove unused gps_position_valid() function

src/modules/navigator/course.cpp

@@ -117,5 +117,3 @@ Course::update_setpoint_triplet()
 
 	_navigator->set_position_setpoint_triplet_updated();
 }
-
-

src/modules/navigator/navigator.h

@@ -189,11 +189,6 @@ public:
 
 	bool home_global_position_valid() { return (_home_pos.valid_alt && _home_pos.valid_hpos); }
 
-	/**
-	 * Check if GPS position is valid (has recent 3D fix)
-	 */
-	bool gps_position_valid() { return (_gps_pos.fix_type >= 3) && (hrt_elapsed_time(&_gps_pos.timestamp) < 2_s); }
-
 	Geofence &get_geofence() { return _geofence; }
 
 	float get_default_loiter_rad() { return fabsf(_param_nav_loiter_rad.get()); }