bip: fix uart interrupt type to both
bip: fix uart interrupt type to both

ITE only supports both edge triggers for GPB0 instead
of just falling.

BRANCH=none
BUG=79942824
TEST=nothing is changing on how it configured.
We are just changing the documentation in gpio.inc

Change-Id: Ib7af54e360f4acaf410fb64b6747caf4d8729cec
Signed-off-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1066310
Reviewed-by: Aaron Durbin <af0622ab041e8b0f8e5819838dcc93898196e71f@chromium.org>

coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec,coreboot/chrome-ec