ArmVirtPkg: CloudHv: Add a NULL implementation of ArmCcaConfigureMmio

To support Arm CCA, a hook function ArmCcaConfigureMmio () has
been added to the ArmVirtMemInfoLib library.

Since, Arm CCA has not been enabled for the Cloud Hypervisor guest
firmware, update the CloudHvVirtMemInfoLib library to add a NULL
implementation for ArmCcaConfigureMmio () that returns
RETURN_UNSUPPORTED.

Signed-off-by: Sami Mujawar <sami.mujawar@arm.com>