liara: Reduce input voltage to 5V when battery full
liara: Reduce input voltage to 5V when battery full

To reduce power consumption, reduce USB-C PD input voltage to 5V
when the battery is full and the system is off (S5/G3).

BUG=b:121383620
BRANCH=grunt
TEST=battery 90%: chgsup shows 15V or 20V,
     when battery full: chgsup shows 5V,
     power on AP: chgsup shows 15V or 20V

Change-Id: I377bc02ca5ec352619b05ef619c7a9e184f547cb
Signed-off-by: Edward Hill <db1406b34e091703092b6b136bdfeb2c8125fc0e@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1401018
Reviewed-by: Jett Rink <9d4aef0593e6843318d99df31597fb6153b89787@chromium.org>

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