Adding tests for Realm payload

This testing patch has the following test scenarios for realm payload:

1. Query the RMI Version on a single CPU.
2. Multi CPU version query.
3. Test to delegate and undelegate a buffer using RMI Delegate and
Undelegate commands.

Signed-off-by: Mark Dykes <mark.dykes@arm.com>
Change-Id: I3404b903b5b4f044a91ce824a408e7cf355a7589
9 files changed