vboot_api: Remove unused VB_SCREEN constants

Some of the defined screens have never been used or we've stopped using
them a while ago. Remove the respective constants to make it clearer
that callers of the library are not expected to handle them.

CQ-DEPEND=CL:903362
BRANCH=None
BUG=None
TEST=make runtests

Change-Id: I82308fc76dc10b2c8b408af7a15a819120043632
Signed-off-by: Julius Werner <jwerner@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/902899
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Reviewed-by: Randall Spangler <rspangler@chromium.org>
2 files changed