feat: add el3 attestation token signing

This adds build and coverity coverage for the new build option
RMMD_ENABLE_EL3_TOKEN_SIGN.

Change-Id: Ib9405c5b33f2885b8aefa450106a2804376e1ba0
Signed-off-by: Raghu Krishnamurthy <raghupathyk@nvidia.com>
2 files changed