elm win: change to use legacy api for cocoa engine

Some APIs are move from eo to legacy as in ab3058d3,
but not all api calls are changed. This causes build break
in mac with cocoa backend.
This patch fixes it.

@fix

src/lib/elementary/elm_win.c

@@ -5629,7 +5629,7 @@ _elm_win_window_id_get(Eo *obj EINA_UNUSED, Elm_Win_Data *sd)
         if (sd->parent)
           {
              Ecore_Cocoa_Window *pwin;
-             pwin = elm_obj_win_cocoa_window_get(sd->parent);
+             pwin = elm_win_cocoa_window_get(sd->parent);
              return (Ecore_Window)pwin;
           }
 #endif