commit 41ccec35 upstream.

This fixes a BUG_ON(bo->sync_obj != NULL); in ttm_bo_release_list.
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>