drm/i915: quirk away broken OpRegion VBT

commit 25e341cfc33d94435472983825163e97fe370a6c upstream.

Somehow the BIOS manages to screw things up when copying the VBT
around, because the one we scrap from the VBIOS rom actually works.

Tested-by: Markus Heinz <markus.heinz@uni-dortmund.de>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=28812
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>