octopus: upgrade ps8751 firmware if present

Determine if the PS8751 is present on the expected port. If it is, then
schedule a firmware update check.

BRANCH=none
BUG=b:78334391
TEST=firmware successfully updates if PS8751 is present and has another
version of firmware on it.

Change-Id: I827408d169a5566f45dd834ca825b31e20c3c805
Signed-off-by: Jett Rink <jettrink@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1117266
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
4 files changed