libweston-desktop: Fix some clang warnings

Fixes:

implicit conversion from enumeration type '...' to different
enumeration type '...' [-Wenum-conversion]

Signed-off-by: Armin Krezović <krezovic.armin@gmail.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
diff --git a/libweston-desktop/wl-shell.c b/libweston-desktop/wl-shell.c
index ded69f7..b5ad334 100644
--- a/libweston-desktop/wl-shell.c
+++ b/libweston-desktop/wl-shell.c
@@ -231,8 +231,10 @@
 	struct weston_seat *seat = wl_resource_get_user_data(seat_resource);
 	struct weston_desktop_wl_shell_surface *surface =
 		weston_desktop_surface_get_implementation_data(dsurface);
+	enum weston_desktop_surface_edge surf_edges =
+		(enum weston_desktop_surface_edge) edges;
 
-	weston_desktop_api_resize(surface->desktop, dsurface, seat, serial, edges);
+	weston_desktop_api_resize(surface->desktop, dsurface, seat, serial, surf_edges);
 }
 
 static void