FROMGIT: drm/virtio: implement blob resources: probe for host visible region

The availability of the host visible region means host 3D
allocations can be directly mapped in the guest.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200924003214.662-9-gurchetansingh@chromium.org


Co-developed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>
(cherry picked from commit 6076a9711dc535f1deca8014949beb7fcae8de34
 git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git

 master)

BUG=b:171715474
TEST=compile

Change-Id: I8b83e07a934223acd9548c4629d497f5806d12f1
Signed-off-by: Guenter Roeck <groeck@chromium.org>
(cherry picked from commit f7346453dc95e387b9395b03570c820a45448a50)