soc/amd/stoneyridge: Enable verstage support

Add Kconfig selects for vboot and update the makefile to pick up
files to be used in verstage.

Change-Id: If5c439a330d687156006aec2ebaea18ff2c96b3e
Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Reviewed-on: https://review.coreboot.org/19756
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
2 files changed