perf tools: Convert sort entries to hpp formats

This is a preparation of consolidating management of output field and
sort keys.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Ingo Molnar <mingo@kernel.org>
Link: http://lkml.kernel.org/r/1400480762-22852-3-git-send-email-namhyung@kernel.org
Signed-off-by: Jiri Olsa <jolsa@kernel.org>

tools/perf/ui/hist.c

@@ -284,6 +284,7 @@ struct perf_hpp_fmt perf_hpp__format[] = {
 };
 
 LIST_HEAD(perf_hpp__list);
+LIST_HEAD(perf_hpp__sort_list);
 
 
 #undef HPP__COLOR_PRINT_FNS
@@ -325,6 +326,11 @@ void perf_hpp__column_register(struct perf_hpp_fmt *format)
 	list_add_tail(&format->list, &perf_hpp__list);
 }
 
+void perf_hpp__register_sort_field(struct perf_hpp_fmt *format)
+{
+	list_add_tail(&format->sort_list, &perf_hpp__sort_list);
+}
+
 void perf_hpp__column_enable(unsigned col)
 {
 	BUG_ON(col >= PERF_HPP__MAX_INDEX);