perf report: Generalize perf_session__fprintf_hists()

Pull it out of builtin-report - further changes will be made and it
will then be reusable in 'perf diff' as well.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1260914682-29652-4-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index bceaa09..ce3a6c8 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -108,7 +108,7 @@
 	struct symbol **syms = NULL;
 	unsigned int i;
 
-	if (self->use_callchain) {
+	if (symbol_conf.use_callchain) {
 		syms = calloc(chain->nr, sizeof(*syms));
 		if (!syms) {
 			fprintf(stderr, "Can't allocate memory for symbols\n");
@@ -140,7 +140,7 @@
 			if (sort__has_parent && !*parent &&
 			    symbol__match_parent_regex(al.sym))
 				*parent = al.sym;
-			if (!self->use_callchain)
+			if (!symbol_conf.use_callchain)
 				break;
 			syms[i] = al.sym;
 		}