virgl: Stabilize VIRGL_RENDERER_DRM

Promote VIRGL_RENDERER_DRM to a stable public virglrenderer API.

Signed-off-by: Dmitry Osipenko <dmitry.osipenko@collabora.com>
Part-of: <https://gitlab.freedesktop.org/virgl/virglrenderer/-/merge_requests/1127>
1 file changed