platform/chrome: cros_ec_typec: Handle hard reset

The Chrome Embedded Controller (EC) generates a hard reset type C event
when a USB Power Delivery (PD) hard reset is encountered. Handle this
event by unregistering the partner and cable on the associated port and
clearing the event flag.

Cc: Benson Leung <bleung@chromium.org>
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20210420171617.3830902-2-pmalani@chromium.org