drm/virtio: implement blob resources: implement vram object

drm/virtio: implement blob resources: implement vram object

A virtio-gpu vram object is based on range-based allocation.
No guest shmemfs backing, so we call drm_gem_private_object_init.

This is for host memory without any guest backing (atleast initially).

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20200924003214.662-12-gurchetansingh@chromium.org
Co-developed-by: Gurchetan Singh <gurchetansingh@chromium.org>
Signed-off-by: Gurchetan Singh <gurchetansingh@chromium.org>