[Intel-gfx] drm/i915: LVDS lid patches

[Jesse Barnes]

After some discussion with Matthew this morning, I decided to split this
patchset up a bit.  I'd appreciate acks/reviews on stuff that's ok so we
can get this upstream (the first two fix a real bug), and discussion on
the rest if there are issues.

This work was initially motivated by fdo bug #21230 (first to patches
cover that) but also adds some features that have been missing from our
LVDS support (second two patches).

Thanks,
Jesse