perf stat: Using init_stats instead of memset

The init_stats function is meant to init 'struct stats'.
Reported-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1435310967-14570-21-git-send-email-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-stat.c

@@ -284,7 +284,7 @@ static int process_counter(struct perf_evsel *counter)
 	int i, ret;
 
 	aggr->val = aggr->ena = aggr->run = 0;
-	memset(ps->res_stats, 0, sizeof(ps->res_stats));
+	init_stats(ps->res_stats);
 
 	if (counter->per_pkg)
 		zero_per_pkg(counter);