MMFMWK-8236 waylandsink: need check if the dmabuf format is support by weston

If the dmabuf format is not supported, we should use ion allocator
as it will fallback to shm allocator

upstream status: imx specific
diff --git a/ext/wayland/gstwaylandsink.c b/ext/wayland/gstwaylandsink.c
index f4b32cf..73f8315 100644
--- a/ext/wayland/gstwaylandsink.c
+++ b/ext/wayland/gstwaylandsink.c
@@ -583,7 +583,9 @@
   pool = g_object_new (gst_wayland_pool_get_type (), NULL);
 
 #ifdef HAVE_ION_ALLOCATOR
-  alloc = gst_ion_allocator_obtain ();
+  GstVideoFormat format = GST_VIDEO_INFO_FORMAT (&sink->video_info);
+  if (gst_wl_display_check_format_for_dmabuf (sink->display, format))
+    alloc = gst_ion_allocator_obtain ();
 #endif
 
   structure = gst_buffer_pool_get_config (pool);