bb_retimer: Fix port bounds check
bb_retimer: Fix port bounds check

This fixes a bounds check in the 'bb' command argument parsing.

BRANCH=none
BUG=none
TEST=EC no longer resets when triggering the off-by-one error

Change-Id: I4ff459781c047b3899150485b7fd3fe6363bdec3
Signed-off-by: Caveh Jalali <08e24a66aefda7a55ca7d73f8903e0fb16eec763@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2730521
Reviewed-by: Denis Brockus <6b21e8190fb5e373363fb95271367073a16474ef@chromium.org>

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