This allows us to specify the polarity of the alert signal for
each TCPC chip onboard, even if we have multiple instances of
the same chip.
BUG=none
BRANCH=none
TEST=built and booted on reef
Change-Id: I06a58c4e26892843243e8e98f2c86c6d3a696eb1
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/360948
Reviewed-by: Shawn N <shawnn@chromium.org>