Plane: Replace update_vel_controller_xy() with update_xy_controller()

ArduPlane/quadplane.cpp

@@ -2250,7 +2250,7 @@ void QuadPlane::vtol_position_controller(void)
         pos_control->set_desired_accel_xy(0.0f,0.0f);
 
         // run horizontal velocity controller
-        pos_control->update_vel_controller_xy();
+        pos_control->update_xy_controller();
 
         // nav roll and pitch are controller by position controller
         plane.nav_roll_cd = pos_control->get_roll();