Expand this to 4KB so that it is possible to add custom information to it.
On Chromebooks this is used to pass verified-boot information.
Signed-off-by: Simon Glass <sjg@chromium.org>
Add the definition of this structure common to Intel devices. It includes
some optional Chrome OS pieces which are used when vboot is integrated.
Drop the APL version as it is basically the same.
Signed-off-by: Simon Glass <sjg@chromium.org>