firmware: Remove deprecated SW_WP_ENABLED flag

This was deprecated months ago in crossystem, and isn't set by
depthcharge or coreboot.  Remove the flag from vboot as well, keeping
only a reminder in vboot_struct.h so we don't reuse the VbSharedData
bit.

BUG=chromium:742685
BRANCH=none
TEST=make runtests

Change-Id: Ifa928e8ec4d999c524c6f4168695859261f384c9
Signed-off-by: Randall Spangler <rspangler@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/947256
Reviewed-by: Julius Werner <jwerner@chromium.org>
(cherry picked from commit 7bb45097af1e8b5f2bcf8e7a8bc6557c6505693b)
Reviewed-on: https://chromium-review.googlesource.com/949621
Reviewed-by: Furquan Shaikh <furquan@chromium.org>
Commit-Queue: Furquan Shaikh <furquan@chromium.org>
Tested-by: Furquan Shaikh <furquan@chromium.org>
Trybot-Ready: Furquan Shaikh <furquan@chromium.org>
6 files changed