AP_Landing: use past_interval_finish_line and line_path_proportion from Location

libraries/AP_Landing/AP_Landing_Deepstall.cpp

@@ -281,8 +281,8 @@ bool AP_Landing_Deepstall::verify_land(const Location &prev_WP_loc, Location &ne
         memcpy(&entry_point, &landing_point, sizeof(Location));
         entry_point.offset_bearing(target_heading_deg + 180.0, travel_distance);
 
-        if (!location_passed_point(current_loc, arc_exit, entry_point)) {
-            if (location_passed_point(current_loc, arc_exit, extended_approach)) {
+        if (!current_loc.past_interval_finish_line(arc_exit, entry_point)) {
+            if (current_loc.past_interval_finish_line(arc_exit, extended_approach)) {
                 // this should never happen, but prevent against an indefinite fly away
                 stage = DEEPSTALL_STAGE_FLY_TO_LANDING;
             }

libraries/AP_Landing/AP_Landing_Slope.cpp

@@ -303,7 +303,7 @@ void AP_Landing::type_slope_setup_landing_glide_slope(const Location &prev_WP_lo
     target_altitude_offset_cm = loc.alt - prev_WP_loc.alt;
 
     // calculate the proportion we are to the target
-    float land_proportion = location_path_proportion(current_loc, prev_WP_loc, loc);
+    float land_proportion = current_loc.line_path_proportion(prev_WP_loc, loc);
 
     // now setup the glide slope for landing
     set_target_altitude_proportion_fn(loc, 1.0f - land_proportion);