PEPPY/HASWELL: move more support functions from mainboard to the intel i915 driver

Move (and rename to make it clearer) the function that computes display
parameters from the dpcd and edid.

BUG=None
TEST=Build and boot on peppy. Doesn't break falco other builds.
BRANCH=None

Change-Id: Idfbb56fd312b23c742c52abca1a34ae117a8fece
Signed-off-by: Ronald G. Minnich <rminnich@google.com>
Reviewed-on: https://chromium-review.googlesource.com/171366
Reviewed-by: Furquan Shaikh <furquan.m.shaikh@gmail.com>
Reviewed-by: Ronald Minnich <rminnich@chromium.org>
Tested-by: Ronald Minnich <rminnich@chromium.org>
Commit-Queue: Ronald Minnich <rminnich@chromium.org>
6 files changed