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/lib_powerpc/multi.c b/post/lib_powerpc/multi.c
index e42a7c0..5845616 100644
--- a/post/lib_powerpc/multi.c
+++ b/post/lib_powerpc/multi.c
@@ -57,7 +57,7 @@
 	    ASM_BLR,
 	};
 
-	for (i = 0; i < sizeof(src) / sizeof(src[0]); i ++)
+	for (i = 0; i < ARRAY_SIZE(src); ++i)
 	{
 	    src[i] = i;
 	    dst[i] = 0;