platform/chrome: cros_ec_typec: Register Type C switches

Register Type C mux and switch handles, when provided via firmware
bindings. These will allow the cros-ec-typec driver, and also alternate
mode drivers to configure connected Muxes correctly, according to PD
information retrieved from the Chrome OS EC.

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