gstreamer: Add gst_format to the table of supported formats
gstreamer: Add gst_format to the table of supported formats

This format is required to add metadata to the source buffer
using gst_buffer_add_video_meta_full.
This metadata can be used to pass strides/offsets, or
dmabuf-specific information.

Signed-off-by: Frediano Ziglio <55d48b080b2e443e395cde84d2c83b135a4ff48e@redhat.com>
Acked-by: Christophe Fergeau <05b95054a663c388a4e33d95828cb30f0370f8ef@redhat.com>

fgouget/spice,fgouget/spice,fgouget/spice,fgouget/spice