spring: Setting for USB voltage sense ADC

This changes ID pin sensing to VBUS sensing.

BUG=chrome-os-partner:14319
TEST=Build success.
BRANCH=none

Change-Id: I179f7ab891f83d5c50ec7766372ba8826b3cd231
Signed-off-by: Vic Yang <victoryang@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/40154
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>
2 files changed