Add metric group descriptions created by:
https://github.com/intel/perfmon/blob/main/scripts/create_perf_json.py
The descriptions add some additional detail in perf list.

Committer notes:

Removed unrelated changes to tools/perf/pmu-events/arch/x86/mapfile.csv
that removed AMD mappings and ended up breaking the build with things
like:

    CC      /tmp/build/perf-tools-next/pmu-events/pmu-events.o
  /tmp/build/perf-tools-next/pmu-events/pmu-events.c:23808:39: error: ‘pmu_metrics__amdzen4’ defined but not used [-Werror=unused-const-variable=]
  23808 | static const struct compact_pmu_event pmu_metrics__amdzen4[] = {
        |                                       ^~~~~~~~~~~~~~~~~~~~
  /tmp/build/perf-tools-next/pmu-events/pmu-events.c:23316:39: error: ‘pmu_events__amdzen4’ defined but not used [-Werror=unused-const-variable=]
  23316 | static const struct compact_pmu_event pmu_events__amdzen4[] = {
        |                                       ^~~~~~~~~~~~~~~~~~~
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Link: https://lore.kernel.org/r/20230517173805.602113-16-irogers@google.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>