MMFMWK-8242 waylandsink: fix crash when create buffer pool

need use caps to generate video info

upstream status: imx specific
diff --git a/ext/wayland/gstwaylandsink.c b/ext/wayland/gstwaylandsink.c
index bbab8de..af067fd 100644
--- a/ext/wayland/gstwaylandsink.c
+++ b/ext/wayland/gstwaylandsink.c
@@ -596,7 +596,9 @@
   pool = g_object_new (gst_wayland_pool_get_type (), NULL);
 
 #ifdef HAVE_ION_ALLOCATOR
-  GstVideoFormat format = GST_VIDEO_INFO_FORMAT (&sink->video_info);
+  GstVideoInfo info;
+  gst_video_info_from_caps (&info, caps);
+  GstVideoFormat format = GST_VIDEO_INFO_FORMAT (&info);
   if (gst_wl_display_check_format_for_dmabuf (sink->display, format))
     alloc = gst_ion_allocator_obtain ();
 #endif