perf parse-event: Fix cpu map leaks

Like evlist cpu map, evsel's cpu map should have a proper refcount.
As it's created with a refcount, we don't need to get an extra count.
Thanks to Arnaldo for the simpler suggestion.

This fixes the following ASAN report:

  Direct leak of 840 byte(s) in 70 object(s) allocated from:
    #0 0x7fe36703f628 in malloc (/lib/x86_64-linux-gnu/libasan.so.5+0x107628)
    #1 0x559fbbf611ca in cpu_map__trim_new /home/namhyung/project/linux/tools/lib/perf/cpumap.c:79
    #2 0x559fbbf6229c in perf_cpu_map__new /home/namhyung/project/linux/tools/lib/perf/cpumap.c:237
    #3 0x559fbbcc6c6d in __add_event util/parse-events.c:357
    #4 0x559fbbcc6c6d in add_event_tool util/parse-events.c:408
    #5 0x559fbbcc6c6d in parse_events_add_tool util/parse-events.c:1414
    torvalds#6 0x559fbbd8474d in parse_events_parse util/parse-events.y:439
    torvalds#7 0x559fbbcc95da in parse_events__scanner util/parse-events.c:2096
    torvalds#8 0x559fbbcc95da in __parse_events util/parse-events.c:2141
    torvalds#9 0x559fbbc2788b in check_parse_id tests/pmu-events.c:406
    torvalds#10 0x559fbbc2788b in check_parse_id tests/pmu-events.c:393
    torvalds#11 0x559fbbc2788b in check_parse_fake tests/pmu-events.c:436
    torvalds#12 0x559fbbc2788b in metric_parse_fake tests/pmu-events.c:553
    torvalds#13 0x559fbbc27e2d in test_parsing_fake tests/pmu-events.c:599
    torvalds#14 0x559fbbc27e2d in test_parsing_fake tests/pmu-events.c:574
    torvalds#15 0x559fbbc0109b in run_test tests/builtin-test.c:410
    torvalds#16 0x559fbbc0109b in test_and_print tests/builtin-test.c:440
    torvalds#17 0x559fbbc03e69 in __cmd_test tests/builtin-test.c:695
    torvalds#18 0x559fbbc03e69 in cmd_test tests/builtin-test.c:807
    torvalds#19 0x559fbbc691f4 in run_builtin /home/namhyung/project/linux/tools/perf/perf.c:312
    torvalds#20 0x559fbbb071a8 in handle_internal_command /home/namhyung/project/linux/tools/perf/perf.c:364
    torvalds#21 0x559fbbb071a8 in run_argv /home/namhyung/project/linux/tools/perf/perf.c:408
    torvalds#22 0x559fbbb071a8 in main /home/namhyung/project/linux/tools/perf/perf.c:538
    torvalds#23 0x7fe366b68cc9 in __libc_start_main ../csu/libc-start.c:308

And I've failed which commit introduced this bug as the code was
heavily changed since then. ;-/

Acked-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

tools/perf/util/parse-events.c

@@ -365,7 +365,7 @@ __add_event(struct list_head *list, int *idx,
 	}
 
 	(*idx)++;
-	evsel->core.cpus   = perf_cpu_map__get(cpus);
+	evsel->core.cpus = cpus;
 	evsel->core.own_cpus = perf_cpu_map__get(cpus);
 	evsel->core.system_wide = pmu ? pmu->is_uncore : false;
 	evsel->auto_merge_stats = auto_merge_stats;