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/drivers/memory.c b/post/drivers/memory.c
index 3f47449..4cca035 100644
--- a/post/drivers/memory.c
+++ b/post/drivers/memory.c
@@ -225,7 +225,7 @@
 static int memory_post_dataline(unsigned long long * pmem)
 {
 	unsigned long long temp64 = 0;
-	int num_patterns = sizeof(pattern)/ sizeof(pattern[0]);
+	int num_patterns = ARRAY_SIZE(pattern);
 	int i;
 	unsigned int hi, lo, pathi, patlo;
 	int ret = 0;