navigator: use common "acceptance radius" parameter for all modes

src/modules/navigator/navigator_main.cpp

@@ -123,7 +123,7 @@ Navigator::Navigator() :
 	_rtl(this, "RTL"),
 	_update_triplet(false),
 	_param_loiter_radius(this, "LOITER_RAD"),
-	_param_takeoff_acceptance_radius(this, "TF_ACC_RAD")
+	_param_acceptance_radius(this, "ACC_RAD")
 {
 	/* Create a list of our possible navigation types */
 	_navigation_mode_array[0] = &_mission;