platform/chrome: cros_typec_switch: Register mode switches

Register mode switch devices for Type-C connectors, when they are
specified by firmware. These control Type-C configuration for any USB
Type-C mode switches (sometimes known as "muxes") which are controlled
by the ChromeOS EC.

Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220816214857.2088914-6-pmalani@chromium.org