perf kmem: use ARRAY_SIZE instead of reinventing it

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1356030701-16284-8-git-send-email-sasha.levin@oracle.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-kmem.c

@@ -609,8 +609,7 @@ static struct sort_dimension *avail_sorts[] = {
 	&pingpong_sort_dimension,
 };
 
-#define NUM_AVAIL_SORTS	\
-	(int)(sizeof(avail_sorts) / sizeof(struct sort_dimension *))
+#define NUM_AVAIL_SORTS	((int)ARRAY_SIZE(avail_sorts))
 
 static int sort_dimension__add(const char *tok, struct list_head *list)
 {