rtl_direct: Rtl estimate only needs valid destination, not home position

src/modules/navigator/rtl_direct.h

@@ -126,6 +126,12 @@ private:
 	 */
 	void set_rtl_item();
 
+	/**
+	 * @brief sanitize land_approach
+	 *
+	 */
+	loiter_point_s sanitizeLandApproach(loiter_point_s land_approach) const;
+
 	/**
 	 * Check for parameter changes and update them if needed.
 	 */