drm/virtio: implement blob resources: refactor UUID code somewhat

For upcoming blob resources, userspace can specify that the
resource will be used for cross-device sharing. This is mainly
for exportable blobs that will only shared with the virtgpu
display but not across devices.

Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
Acked-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200924003214.662-15-gurchetansingh@chromium.org


Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>