The RMM (Realm Management Monitor) provides functionality that can be
accessed by SMC calls from the host.
The SMC definitions are based on DEN0137[1] version 1.0-rel0
[1] https://developer.arm.com/documentation/den0137/1-0rel0/
Reviewed-by: Gavin Shan <gshan@xxxxxxxxxx>
Signed-off-by: Steven Price <steven.price@xxxxxxx>