ryu: fix power button polarity

The power button signal is driven from the silego part.
It's active high when the button is pressed.

BUG=None
BRANCH=None
TEST=Booted with power button pressed. vboot saw the press and
     requested a shut down.

Change-Id: Ifff1bd8d4340849e0c218812fd401b61c90c5743
Signed-off-by: Patrick Georgi <pgeorgi@chromium.org>
Original-Commit-Id: b6bd7c0de38e1078b85f1671493c6d2948d43149
Original-Change-Id: If25ebce28c1ab5a363f3b4b5ab9fc24baebad56a
Original-Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/214847
Original-Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Reviewed-on: http://review.coreboot.org/9028
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
3 files changed