Add a interface, which is implemented by SoC.
Change-Id: I5524732f6eb3841e43afd176644119b03b5e5e27
Signed-off-by: Xiang Wang <wxjstz@126.com>
Reviewed-on: https://review.coreboot.org/28372
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
