perf probe: Fix to delete multiple probe event

When we put an event with multiple probes, perf-probe fails to delete
with filters. This comes from a failure to list up the event name
because of overwrapping its name.

To fix this issue, skip to list up the event which has same name.

Without this patch:

  # perf probe -l \*
    probe_perf:map__map_ip (on perf_sample__fprintf_brstackoff:21@
    probe_perf:map__map_ip (on perf_sample__fprintf_brstackoff:25@
    probe_perf:map__map_ip (on append_inlines:12@util/machine.c in
    probe_perf:map__map_ip (on unwind_entry:19@util/machine.c in /
    probe_perf:map__map_ip (on map__map_ip@util/map.h in /home/mhi
    probe_perf:map__map_ip (on map__map_ip@util/map.h in /home/mhi
  # perf probe -d \*
  "*" does not hit any event.
    Error: Failed to delete events. Reason: No such file or directory (Code: -2)

With it:

  # perf probe -d \*
  Removed event: probe_perf:map__map_ip
  #

Fixes: 72363540c0 ("perf probe: Support multiprobe event")
Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Reported-by: He Zhe <zhe.he@windriver.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: stable@vger.kernel.org
Link: http://lore.kernel.org/lkml/158287666197.16697.7514373548551863562.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/probe-file.c

@@ -206,6 +206,9 @@ static struct strlist *__probe_file__get_namelist(int fd, bool include_group)
 		} else
 			ret = strlist__add(sl, tev.event);
 		clear_probe_trace_event(&tev);
+		/* Skip if there is same name multi-probe event in the list */
+		if (ret == -EEXIST)
+			ret = 0;
 		if (ret < 0)
 			break;
 	}