Add documentation which describes how to build and sign a coreboot image
which enables vboot.
TEST=None
Change-Id: Ie17b8443772f596de0c9d8afe6f4ec3ac4d4fef8
Signed-off-by: Lee Leahy <Leroy.P.Leahy@intel.com>
Reviewed-on: https://review.coreboot.org/19534
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>