vboot: remove EC nvdata storage

No supported devices still use this, and there's an ongoing cleanup to
remove it.

BUG=b:178689388
BRANCH=none
TEST=compiles

Signed-off-by: Jack Rosenthal <jrosenth@chromium.org>
Change-Id: I3b8363e924a4e035d5a6a572126b39902875e227
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/depthcharge/+/2668065
Reviewed-by: Joel Kitching <kitching@chromium.org>
5 files changed