platform/chrome: cros_ec_typec: Register port altmodes

Instead of using manually managed altmode structs, register the port's
altmodes with the Type-C framework. This facilitates matching them to
partner altmodes later.

Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20220712210318.2671292-2-pmalani@chromium.org