perf test: Fix test case 23 for s390 z/VM or KVM guests

On s390 perf can be executed on a LPAR with support for hardware events
(i. e. cycles) or on a z/VM or KVM guest where no hardware events are
supported. In this environment use software event named cpu-clock for
this test case.

Use the cpuid infrastructure functions to determine the cpuid on s390
which contains an indication of the cpu counter facility availability.

Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Reviewed-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20180213151419.80737-4-tmricht@linux.vnet.ibm.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>