platform/chrome: cros_ec_typec: Use workqueue for port update

Use a work queue to call the port update routines, instead of doing it
directly in the PD notifier callback. This will prevent other drivers
with PD notifier callbacks from being blocked on the port update routine
completing.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>