feat(errata_abi): errata management firmware interface

feat(errata_abi): errata management firmware interface

This patch adds the errata management firmware interface for lower ELs
to discover details about CPU erratum. Based on the CPU erratum
identifier the interface enables the OS to find the mitigation of an
erratum in EL3.

The ABI can only be present in a system that is compliant with SMCCCv1.1
or higher. This implements v1.0 of the errata ABI spec.

For details on all possible return values, refer the design
documentation below:

ABI design documentation:
https://developer.arm.com/documentation/den0100/1-0?lang=en

Signed-off-by: Sona Mathew <SonaRebecca.Mathew@arm.com>
Change-Id: I70f0e2569cf92e6e02ad82e3e77874546232b89a