perf stat: Rename perf_stat struct into perf_stat_evsel

It's used as the perf_evsel::priv data, so the name suits better. Also
we'll need the perf_stat name free for more generic struct.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Kan Liang <kan.liang@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1444992092-17897-29-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/stat.h b/tools/perf/util/stat.h
index 62448c8..f8d9d5c 100644
--- a/tools/perf/util/stat.h
+++ b/tools/perf/util/stat.h
@@ -20,7 +20,7 @@
 	PERF_STAT_EVSEL_ID__MAX,
 };
 
-struct perf_stat {
+struct perf_stat_evsel {
 	struct stats		res_stats[3];
 	enum perf_stat_evsel_id	id;
 };