KVM: s390: selftests: Add regression tests for PLO subfunctions

Extend the existing regression test framework for s390x CPU subfunctions
to include tests for the Perform Locked Operation (PLO) subfunction
functions.

PLO was introduced in the very first 64-bit machine generation.
Hence it is assumed PLO is always installed in the Z Arch.
The test procedure follows the established pattern.

Suggested-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Hariharan Mari <hari55@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Christoph Schlameuss <schlameuss@linux.ibm.com>
Link: https://lore.kernel.org/r/20240823130947.38323-6-hari55@linux.ibm.com


Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
Message-ID: <20240823130947.38323-6-hari55@linux.ibm.com>