drm/i915: panel: invert brightness acer aspire 5734z

drm/i915: panel: invert brightness acer aspire 5734z

commit 5a15ab5b93e4a3ebcd4fa6c76cf646a45e9cf806 upstream.

Mark the Acer Aspire 5734Z that this machines requires the module to
invert the panel backlight brightness value after reading from and prior
to writing to the PCI configuration space.

Signed-off-by: Carsten Emde <C.Emde@osadl.org>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>