perf test: Use generic event for expand_libpfm_events()

I found that the UNHALTED_CORE_CYCLES event is only available in the
Intel machines and it makes other vendors/archs fail on the test.  As
libpfm4 can parse the generic events like cycles, let's use them.

Fixes: 40b74c30 ("perf test: Add expand cgroup event test")
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20201027072855.655449-1-namhyung@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/expand-cgroup.c

@@ -145,7 +145,7 @@ static int expand_libpfm_events(void)
 	int ret;
 	struct evlist *evlist;
 	struct rblist metric_events;
-	const char event_str[] = "UNHALTED_CORE_CYCLES";
+	const char event_str[] = "CYCLES";
 	struct option opt = {
 		.value = &evlist,
 	};