scarlet: Enable AP throttling for battery under-voltage
scarlet: Enable AP throttling for battery under-voltage

BUG=b:73050145
BRANCH=scarlet
TEST=manually test on scarlet together with CL:1064983

Change-Id: Ic5bcc0e4432b2f8ac03fcfa872388ff07d240a7b
Signed-off-by: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1064985
Commit-Ready: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>
Tested-by: Philip Chen <3ee404f9ef892bc3fda6e6a76e65843b5fa44db2@chromium.org>
Reviewed-by: David Schneider <f6dc7060de10912bba612c52f98c21c17bd19e92@chromium.org>
Reviewed-by: Nicolas Boichat <f3daba1cdc403799935674d3cd4b0e5bd1804232@chromium.org>

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