Introduce a new SiP SVC subsystem to provide ARM Silicon Provider based
supervisory call services. SiP SVC service provides the capability to
send SMC/HVC call from kernel running at EL1 to hypervisor/
secure monitor firmware running at EL2/EL3 and also added SiP SVC shell
commands to exercise the service.
Signed-off-by: Mahesh Rao <mahesh.rao@intel.com>