futility: show: Print keyblock signature size and data size

To allow easier debugging for key mismatch issues, print keyblock
signature size and data size for the 'futility show' subcommand.

BUG=none
TEST=make -j runfutiltests
BRANCH=none

Change-Id: Iee2f6439f19ea1f0018a47a41161f44b46e156ee
Signed-off-by: Yu-Ping Wu <yupingso@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/5629600
Reviewed-by: Julius Werner <jwerner@chromium.org>
35 files changed