Add basic supported mailbox commands for this embedded contrlller,
and define some command functions to retrieve and print information
about the EC.
Change-Id: Ibcef7d58e1852fdb2e52b97acd4b51a26dd8cd77
Signed-off-by: Duncan Laurie <dlaurie@google.com>
Reviewed-on: https://review.coreboot.org/29115
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
