platform/chrome: cros_typec_vdm: Add VDM send support

Add support to send generic VDM messages from the alt mode driver to the
partner (via the ChromeOS EC). The function introduced here is intended
to be called by the alt mode driver (via the Type-C bus logic).

Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Prashant Malani <pmalani@chromium.org>
Reviewed-by: Benson Leung <bleung@chromium.org>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Link: https://lore.kernel.org/r/20221228004648.793339-11-pmalani@chromium.org