Introduce a driver to configure USB Type-C mode switches and retimers
which are controlled by the ChromeOS EC (Embedded Controller).
This allows Type-C port drivers, as well as alternate mode drivers to
configure their relevant mode switches and retimers according to the
Type-C state they want to achieve.

ACPI devices with ID GOOG001A will bind to this driver.

Currently, we only register a retimer switch with a stub set function.
Subsequent patches will implement the host command set functionality,
and introduce mode switches.
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Tzung-Bi Shih <tzungbi@kernel.org>
Link: https://lore.kernel.org/r/20220816214857.2088914-3-pmalani@chromium.org