Attest: attest_token_start()/finish() for symmetric Initial Attestation

Implement attest_token_start() and attest_token_finish() for
symmetric key algorithm based Initial Attestation.
attest_token_start() and attest_token_finish() call COSE_Mac0 APIs
from t_cose library.

Change-Id: Idb33f33a2f531a13aa217171fcd007d71f8164bb
Signed-off-by: David Hu <david.hu@arm.com>
3 files changed