drm: Do a full device unregister when unplugging

drm: Do a full device unregister when unplugging

Rather than do a partial unregister of just the minors, unregister the
device (drm_dev_unregister(), and so remove all userspace interfaces,
when the device is unplugged (drm_unplug_dev()).

Signed-off-by: Chris Wilson <[email protected]>
Cc: David Airlie <[email protected]>
Cc: Daniel Vetter <[email protected]>
Cc: Laurent Pinchart <[email protected]>
Cc: Alexey Brodkin <[email protected]>
Cc: Amitoj Kaur Chawla <[email protected]>
Cc: [email protected]
Signed-off-by: Daniel Vetter <[email protected]>
Link: http://patchwork.freedesktop.org/patch/msgid/[email protected]