xdg-shell: Remove the flags from get_xdg_popup

There haven't been any ideas for flags, so we don't need a useless,
unused parameter hanging around. Any future ideas should be done with a
new request entirely.

Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>

clients/window.c

@@ -4840,8 +4840,7 @@ window_show_menu(struct display *display,
 						    input->seat,
 						    display_get_serial(window->display),
 						    window->x - ix,
-						    window->y - iy,
+						    window->y - iy);
-						    0);
 	fail_on_null(window->xdg_popup);
 
 	xdg_popup_set_user_data(window->xdg_popup, window);

desktop-shell/shell.c

@@ -4073,7 +4073,7 @@ xdg_get_xdg_popup(struct wl_client *client,
 		  struct wl_resource *parent_resource,
 		  struct wl_resource *seat_resource,
 		  uint32_t serial,
-		  int32_t x, int32_t y, uint32_t flags)
+		  int32_t x, int32_t y)
 {
 	struct weston_surface *surface =
 		wl_resource_get_user_data(surface_resource);

protocol/xdg-shell.xml

@@ -94,7 +94,6 @@
       <arg name="serial" type="uint" summary="serial of the implicit grab on the pointer"/>
       <arg name="x" type="int"/>
       <arg name="y" type="int"/>
-      <arg name="flags" type="uint"/>
     </request>
 
     <event name="ping">