Taken from drm-next d65d31388a23 ("Merge tag
'drm-misc-next-fixes-2017-11-07' of
git://anongit.freedesktop.org/drm/drm-misc into drm-next")
v2: Add the NOTSUPP definition from the final drm-next version, not the
commit (anholt).
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>