drm/virtio: params struct for virtio_gpu_cmd_create_resource_3d()

Add 3d resource parameters to virtio_gpu_object_params struct.  With
that in place we can use it for virtio_gpu_cmd_resource_create_3d()
calls.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Noralf Trønnes <noralf@tronnes.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20190318113332.10900-5-kraxel@redhat.com