Add the protocol definition of the MM communicate 2 protocol,
which has been introduced by version 1.7 errata A of the PI spec.
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Ard Biesheuvel