krabby: enable vcc1.8v
krabby: enable vcc1.8v

Set GPMx voltage to 1.8V to enable VCC 1.8V for M group.

BUG=none
TEST=`md .b 0x00F016ED`, verify bit 2..4 == 0b100
BRANCH=none

Signed-off-by: Ting Shen <c671d3efec3d7e7e285f3788bf0d1ba4c8605b78@google.com>
Change-Id: Ia4e24694320e9998ea7ee53b0b528e931ddbd227
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3489905
Reviewed-by: Dino Li <00c808bcd0610e8dd73a10880490949c0c589d41@ite.corp-partner.google.com>
Reviewed-by: Eric Yilun Lin <2f2733c7206ea2b76bd2db1905cc5e8a75841c48@google.com>
Commit-Queue: Ting Shen <c671d3efec3d7e7e285f3788bf0d1ba4c8605b78@chromium.org>
Tested-by: Ting Shen <c671d3efec3d7e7e285f3788bf0d1ba4c8605b78@chromium.org>

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