Tools: add Mac0Message support to iatverifier

Add support for the Mac0Message COSE format to iatverifier, as the
alternative to the Sign1Message currently used.

Change-Id: I6baa87209fd17afe52ff1c6f936693e3b9dc9b9f
Signed-off-by: Sergei Trofimov <sergei.trofimov@arm.com>
7 files changed