drm/i915: no-lvds quirk on MSI DC500

This hardware doesn't have an LVDS, it's a desktop box. Fix incorrect
LVDS detection.

Cc: stable@kernel.org
Signed-off-by: Anisse Astier <anisse@astier.eu>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>