Long term, we don't want to support nouveau gl on new cards. Remove the fallback so users without zink will get software rendering instead of nouveau gl. For now, NOUVEAU_USE_ZINK will still select nouveau gl on cards where that is possible, but that isn't really supported and will likely be removed for a lot of cards in the future. Reviewed-by: Karol Herbst <kherbst@redhat.com> Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36971>