i915: implement alignment restrictions

The previous version was a quick and dirty implementation, this one
should be complete.

BUG=chromium:434924
TEST=

Change-Id: Ia6840bd75c7ea1c8d083ae9c5a3da6699f468273
Signed-off-by: Stéphane Marchesin <marcheu@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/231731
Reviewed-by: Haixia Shi <hshi@chromium.org>
1 file changed