This feature is not actually used on current platforms. Avoid setting
up the GPIO unless it is specifically enabled.
BUG=chrome-os-partner:13064
BRANCH=snow
TEST=manual
build and boot on snow. See the AC power GPIO does not change when
un/plugging power.
Change-Id: I6731625a19f30f6dd35471b126f3083b39747203
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/31304
Reviewed-by: David Hendricks <dhendrix@chromium.org>