nct38xx: change rmw operations to use i2c update
nct38xx: change rmw operations to use i2c update

BUG=none
BRANCH=none
TEST=make buildall -j

Change-Id: I93add5d4e3f633ad9ce799576407835b6d1e41e8
Signed-off-by: Denis Brockus <6b21e8190fb5e373363fb95271367073a16474ef@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/1958410
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