perf tools: Make hists__collapse_insert_entry static

No need to export hists__collapse_insert_entry function.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.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/1458823940-24583-4-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index 31c4641..3d34c57 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -1295,8 +1295,9 @@
 	return ret;
 }
 
-int hists__collapse_insert_entry(struct hists *hists, struct rb_root *root,
-				 struct hist_entry *he)
+static int hists__collapse_insert_entry(struct hists *hists,
+					struct rb_root *root,
+					struct hist_entry *he)
 {
 	struct rb_node **p = &root->rb_node;
 	struct rb_node *parent = NULL;