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/srawi.c b/post/lib_powerpc/srawi.c
index be153ad..90a1e4d 100644
--- a/post/lib_powerpc/srawi.c
+++ b/post/lib_powerpc/srawi.c
@@ -61,8 +61,7 @@
 	0xf0000000
     },
 };
-static unsigned int cpu_post_srawi_size =
-    sizeof (cpu_post_srawi_table) / sizeof (struct cpu_post_srawi_s);
+static unsigned int cpu_post_srawi_size = ARRAY_SIZE(cpu_post_srawi_table);
 
 int cpu_post_test_srawi (void)
 {