libweston-desktop: fix sending the configure event with wl_shell

Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
diff --git a/libweston-desktop/wl-shell.c b/libweston-desktop/wl-shell.c
index b5ad334..695b4a3 100644
--- a/libweston-desktop/wl-shell.c
+++ b/libweston-desktop/wl-shell.c
@@ -69,6 +69,7 @@
 
 	if ((wsurface->width == width && wsurface->height == height) ||
 	    (width == 0 && height == 0))
+		return;
 
 	wl_shell_surface_send_configure(surface->resource,
 					WL_SHELL_SURFACE_RESIZE_NONE,