perf hists: Move sort__need_collapse into struct perf_hpp_list

Now we have sort dimensions private for struct hists, we need to make
dimension booleans hists specific as well.

Moving sort__need_collapse into struct perf_hpp_list.

Adding hists__has macro to easily access this info perf struct hists
object.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
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/1462276488-26683-2-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-diff.c b/tools/perf/builtin-diff.c
index 8053a8c..9ce354f 100644
--- a/tools/perf/builtin-diff.c
+++ b/tools/perf/builtin-diff.c
@@ -428,7 +428,7 @@
 	struct rb_root *root;
 	struct rb_node *next;
 
-	if (sort__need_collapse)
+	if (hists__has(hists, need_collapse))
 		root = &hists->entries_collapsed;
 	else
 		root = hists->entries_in;
@@ -450,7 +450,7 @@
 	struct rb_root *root;
 	struct rb_node *next;
 
-	if (sort__need_collapse)
+	if (hists__has(hists, need_collapse))
 		root = &hists->entries_collapsed;
 	else
 		root = hists->entries_in;