drm/i915: ignore LVDS on intel graphics systems that lie about having it

There are a number of small form factor desktop systems with Intel mobile
graphics chips that lie and say they have an LVDS. With kernel mode-setting,
this becomes a problem, and makes native resolution boot go haywire -- for
example, my Dell Studio Hybrid, hooked to a 1920x1080 display claims to
have a 1024x768 LVDS, and the resulting graphical boot on the 1920x1080
display uses only the top left 1024x768, and auto-configured X will end
up only 1024x768 as well. With this change, graphical boot and X
both do 1920x1080 as expected.

Note that we're simply embracing and extending the early bail-out code
in place for the Mac Mini here. The xorg intel driver uses pci subsystem
device and vendor id for matching, while we're using dmi lookups here.
The MSI addition is courtesy of and tested by Bill Nottingham.

Signed-off-by: Jarod Wilson <jarod@redhat.com>
Tested-by: Bill Nottingham <notting@redhat.com>
Signed-off-by: Eric Anholt <eric@anholt.net>