brya: fix the formula of adapter wattage
brya: fix the formula of adapter wattage

BUG=b:212359724, b:212363905
BRANCH=none
TEST=make -j BOARD=gimble

Signed-off-by: Will Tsai <7b3a2764695a2e44000ae6070fceccd181e4303d@wistron.corp-partner.google.com>
Change-Id: I8f2ee2a5e0bce9d1a231070fb284f231c47814cc
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3382607
Reviewed-by: Scott Chao <8cefa9751fac9aaa897ba1213763a96ba8dbd20d@wistron.corp-partner.google.com>
Reviewed-by: caveh jalali <08e24a66aefda7a55ca7d73f8903e0fb16eec763@chromium.org>
Commit-Queue: caveh jalali <08e24a66aefda7a55ca7d73f8903e0fb16eec763@chromium.org>

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