libweston-desktop: Drop (wrongly named) new_buffer in committed

Instead we store the buffer move and just use it when the signal is
fired.

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Jonas Ådahl <jadahl@gmail.com>
diff --git a/libweston-desktop/xdg-shell-v5.c b/libweston-desktop/xdg-shell-v5.c
index 8a1383d..f8943ab 100644
--- a/libweston-desktop/xdg-shell-v5.c
+++ b/libweston-desktop/xdg-shell-v5.c
@@ -188,7 +188,7 @@
 
 static void
 weston_desktop_xdg_surface_committed(struct weston_desktop_surface *dsurface,
-				     void *user_data, bool new_buffer,
+				     void *user_data,
 				     int32_t sx, int32_t sy)
 {
 	struct weston_desktop_xdg_surface *surface = user_data;