drm/virtio: params struct for virtio_gpu_cmd_create_resource()

Add format, width and height fields to the virtio_gpu_object_params
struct.  With that in place we can use the parameter struct for
virtio_gpu_cmd_create_resource() calls too.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20190318113332.10900-4-kraxel@redhat.com