post: use ARRAY_SIZE

We've got a handy dandy macro already for calculating the number of
elements in an array, so use it.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/post/cpu/ppc4xx/spr.c b/post/cpu/ppc4xx/spr.c
index cb18b64..3f5e965 100644
--- a/post/cpu/ppc4xx/spr.c
+++ b/post/cpu/ppc4xx/spr.c
@@ -156,8 +156,7 @@
 	{0x3f3,	"DBDR",		0x00000000,	0x00000000},
 };
 
-static int spr_test_list_size =
-		sizeof (spr_test_list) / sizeof (spr_test_list[0]);
+static int spr_test_list_size = ARRAY_SIZE(spr_test_list);
 
 int spr_post_test (int flags)
 {