perf_counter: Rename list_entry -> group_entry, counter_list -> group_list

This is in preparation of the big rename, but also makes sense
in a standalone way: 'list_entry' is a bad name as we already
have a list_entry() in list.h.

Also, the 'counter list' is too vague, it doesnt tell us the
purpose of that list.

Clarify these names to show that it's all about the group
hiearchy.
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

include/linux/perf_counter.h

@@ -543,7 +543,7 @@ struct perf_pending_entry {
  */
 struct perf_counter {
 #ifdef CONFIG_PERF_COUNTERS
-	struct list_head		list_entry;
+	struct list_head		group_entry;
 	struct list_head		event_entry;
 	struct list_head		sibling_list;
 	int				nr_siblings;
@@ -649,7 +649,7 @@ struct perf_counter_context {
 	 */
 	struct mutex			mutex;
 
-	struct list_head		counter_list;
+	struct list_head		group_list;
 	struct list_head		event_list;
 	int				nr_counters;
 	int				nr_active;