DRM/i915: Add QUIRK_INVERT_BRIGHTNESS for NCR machines.

NCR machines with LVDS panels using Intel chipsets need to have the
QUIRK_INVERT_BRIGHTNESS bit set.
Unfortunately NCR doesn't set a meaningful subvendor/subdevice ID,
therefore we add a DMI dependent quirk list.

Signed-off-by: Egbert Eich <eich@suse.de>
[danvet: fixup whitespace fail.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>