If triggered, many would result in crashes later anyway, so lets change those to asserts. Some are simply useless, so remove those. https://gitlab.gnome.org/GNOME/mutter/merge_requests/584
Nowhere else is it called 'drm_fd' so lets not get rid of this inconsistency. https://gitlab.gnome.org/GNOME/mutter/merge_requests/584
MetaKms* will be a dedicated namespace, which MetaKmsBuffer doesn't fit under. https://gitlab.gnome.org/GNOME/mutter/merge_requests/584