host: Add stub implementation for pkcs11 key

BRANCH=None
BUG=b:347899892
TEST=make runtests # ALL PASS

Change-Id: I69f0a413afc7be0d5455fafeaa1bc9eef465ab52
Signed-off-by: Jakub Czapiga <czapiga@google.com>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/5645522
Reviewed-by: Julius Werner <jwerner@chromium.org>
Commit-Queue: Julius Werner <jwerner@chromium.org>
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>
5 files changed