rambi: use SERIRQ pad as keyboard irq in gpio mode

The level shifting between 3.3V and 1.8V for the SERIRQ
signal is not working. Instead use the SERIRQ pad as
a gpio which is used as a direct IRQ signal for the
keyboard interupt.

BUG=chrome-os-partner:23965
BRANCH=None
TEST=Built and booted rambi. Keyboard works with associated EC change.
CQ-DEPEND=CL:177189

Change-Id: Ifc270ca38207828a6d4711551d4bde9121559cca
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/177223
Tested-by: Bernie Thompson <bhthompson@chromium.org>
Reviewed-on: http://review.coreboot.org/4979
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
4 files changed