linux-phytec-fsl

drm/i915: fix invalid reference handling of the default ctx obj

Otherwise we end up trying to unpin a freed object and BUG.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>