charge_manager: Classify VBUS supplier type

Add a new supplier type for VBUS chargers (USB chargers which supply VBUS
but are not identified as another charger type).

BUG=chrome-os-partner:37168
TEST=Manual on Samus with subsequent kernel commit. Modify code to
reject all non-VBUS suppliers, charge with SDP port, and verify charge
icon appears in OS.
BRANCH=Samus

Signed-off-by: Shawn Nematbakhsh <shawnn@chromium.org>
Change-Id: I5fbdb1cb57bd0224b01aaf5a763f93b678b6d204
Reviewed-on: https://chromium-review.googlesource.com/254346
Reviewed-by: Alec Berg <alecaberg@chromium.org>
3 files changed