platform/chrome: cros_ec_typec: Avoid setting usb role twice during disconnect

On disconnect port partner is removed and usb role is set to NONE.
But then in cros_typec_port_update() the role is set again.
Avoid this by moving usb_role_switch_set_role() to
cros_typec_configure_mux().

Suggested-by: Prashant Malani <pmalani@chromium.org>
Signed-off-by: Azhar Shaikh <azhar.shaikh@intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>