Just a DRM_MASTER flag is sufficient here, though maybe this call is
totally deprecated anyway (xf86-video-intel still calls it though).

(airlied: drop ioctl auth_magic as discussed on mailing list also)
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: NDave Airlie <airlied@redhat.com>