Avoids leaking fbs and associated buffers on release.
Signed-off-by: Kristian Høgsberg <krh@redhat.com> Tested-by: Tested-by: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Dave Airlie <airlied@linux.ie>