perf vendor events: Remove UTF-8 characters from cmn.json

cmn.json contains UTF-8 characters in brief description which
could break the perf build on some distros.

Fix this issue by removing the UTF-8 characters from cmn.json.

without this fix:

  $find tools/perf/pmu-events/ -name "*.json" | xargs file -i | grep -v us-ascii
  tools/perf/pmu-events/arch/arm64/arm/cmn/sys/cmn.json:                   application/json; charset=utf-8

with it:

  $ file -i tools/perf/pmu-events/arch/arm64/arm/cmn/sys/cmn.json
  tools/perf/pmu-events/arch/arm64/arm/cmn/sys/cmn.json: text/plain; charset=us-ascii

Fixes: 0b4de7bd ("perf jevents: Add support for Arm CMN PMU aliasing")
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.com>
Signed-off-by: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jing Zhang <renyu.zj@linux.alibaba.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lore.kernel.org/r/1703138593-50486-1-git-send-email-renyu.zj@linux.alibaba.com


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