vboot: move vboot 2.1 functions and structs into host code

These structs and functions need to stick around for futility
to use, but they are no longer supported in firmware code.

Rename host/lib21/include/* files to end in 21 instead of 2.

BUG=b:124141368, chromium:968464
TEST=make clean && make runtests
BRANCH=none

Change-Id: I01e181e2f03553d60724fbdc826f5ada63777303
Cq-Depend: chromium:1969172
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1963621
Reviewed-by: Julius Werner <jwerner@chromium.org>
Tested-by: Joel Kitching <kitching@chromium.org>
Commit-Queue: Joel Kitching <kitching@chromium.org>
38 files changed