platform_chrome: cros_ec: Add Type-C VDM defines

Add the EC header changes need to support USB Type-C VDM (Vendor Defined
Messages) communication between the system and USB PD-enabled
peripherals.

The headers are already present in the EC code base, from which they've
been ported [1].

[1] https://source.chromium.org/chromium/chromiumos/platform/ec/+/main:include/ec_commands.h



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/20221228004648.793339-3-pmalani@chromium.org