BL2: Provision RoTPK sign policies

For multisignature, if policy support is enabled, provision the
corresponding key policy to the OTP.

For built in keys, also check the signature verification result
against the policy.

Signed-off-by: Maulik Patel <maulik.patel@arm.com>
Change-Id: If91a5967f3cea59cb12546c25f53280a2c7d4cb2
13 files changed