perf test: Fix test perf evlist for z/VM s390x

perf test: Fix test perf evlist for z/VM s390x

Perf test case 'perf evlist tests' fails on z/VM machines on s390.

The failure is causes by event cycles. This event is not available
on virtualized machines like z/VM on s390.

Change to software event cpu-clock to fix this.

    Output before:
      # ./perf test 78
      79: perf evlist tests              : FAILED!
      #

    Output after:
      # ./perf test 78
      79: perf evlist tests              : Ok
      #

Fixes: b04d2b9199129f4f ("perf test: Fix test case perf evlist tests for s390x")
Reviewed-by: Ian Rogers <irogers@google.com>
Reviewed-by: Jan Polensky <japo@linux.ibm.com>
Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Tested-by: Jan Polensky <japo@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Sumanth Korikkar <sumanthk@linux.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>