Backmerge because Chris Wilson needs the very latest&greates of
Gustavo Padovan's sync_file work, specifically the refcounting changes
from:

commit 30cd85dd
Author: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
Date:   Wed Oct 19 15:48:32 2016 -0200

    dma-buf/sync_file: hold reference to fence when creating sync_file

Also good to sync in general since git tends to get confused with the
cherry-picking going on.
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>