platform/chrome: cros_ec: Import Type C host commands

Import the EC_CMD_TYPEC_STATUS and EC_CMD_TYPEC_DISCOVERY Chrome OS EC
host commands from the EC code base [1].

These commands can be used by the application processor to query Power
Delivery (PD) discovery information concerning connected Type C
peripherals.

Also add the EC_FEATURE_TYPEC_CMD feature flag, which is used to
determine whether these commands are supported by the EC.

[1]:
https://chromium.googlesource.com/chromiumos/platform/ec/+/refs/heads/master/include/ec_commands.h



Signed-off-by: Prashant Malani <pmalani@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Link: https://lore.kernel.org/r/20201029222738.482366-5-pmalani@chromium.org