perf hists: Rename hists__fprintf_nr_events to events_stats__fprintf

As this function deals exclusively with hists->stats.

Preparatory patch for removing the by now needless session->hists, that
should be just session->stats.

Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-be0o8si9f1z40cwoa534f7me@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index d3664ab..cb6533b 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -98,7 +98,7 @@
 
 void hists__inc_nr_entries(struct hists *hists, struct hist_entry *h);
 void hists__inc_nr_events(struct hists *self, u32 type);
-size_t hists__fprintf_nr_events(struct hists *self, FILE *fp);
+size_t events_stats__fprintf(struct events_stats *stats, FILE *fp);
 
 size_t hists__fprintf(struct hists *self, bool show_header, int max_rows,
 		      int max_cols, FILE *fp);