drm/i915: Add a dual link lvds quirk for MacBook Pro 8,2

When booting with EFI, Apple botched this one up.

v2: Switch the quirk dmesg output to DRM_INFO.
v3: Actually git add the new things ...

Tested-by: Austin Lund <austin.lund@gmail.com>
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=42842
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>