wayland: use xdg_surface_set_window_geometry

mpv has never used this because we never really seemed to need it, but
it actually has a purpose. This informs the compositor of the actual
dimensions of the mpv window and avoids errors with sizes not matching
(particularly with weston). It's a better way to fix the "maximizing
causing an error on weston" issue since it also works for dmabuf-wayland
(which always had this problem).

video/out/wayland_common.c

@@ -996,6 +996,7 @@ resize:
                mp_rect_w(wl->geometry), mp_rect_h(wl->geometry));
 
     wl->pending_vo_events |= VO_EVENT_RESIZE;
+    xdg_surface_set_window_geometry(wl->xdg_surface, 0, 0, width, height);
     wl->toplevel_configured = true;
 }