drm: Print device information again in debugfs

I was a bit over-eager in my cleanup in

commit 95c081c1
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Tue Jun 21 10:54:12 2016 +0200

    drm: Move master pointer from drm_minor to drm_device

Noticed by Chris Wilson.

Fixes: 95c081c1 ("drm: Move master pointer from drm_minor to drm_device")
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@intel.com>
Cc: Emil Velikov <emil.l.velikov@gmail.com>
Cc: Julia Lawall <julia.lawall@lip6.fr>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>