v2: Support VIRGL_FORMAT_NONE (Gert Wollny) Signed-off-by: Akihiko Odaki <akihiko.odaki@gmail.com> Suggested-by: Gert Wollny <gert.wollny@collabora.com> Reviewed-by: Gert Wollny <gert.wollny@collabora.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15115>