vboot: deprecate Alt OS code

BUG=b:124141368, b:131663912
TEST=make clean && make runtests
BRANCH=none

Change-Id: I6aae5683b8306eede4388ff5ed6665e7769756dc
Signed-off-by: Joel Kitching <kitching@google.com>
Reviewed-on: https://chromium-review.googlesource.com/1588026
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>
Reviewed-by: Ting Shen <phoenixshen@chromium.org>
7 files changed