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/mpc8xx/ether.c b/post/cpu/mpc8xx/ether.c
index 43ea817..fcbb300 100644
--- a/post/cpu/mpc8xx/ether.c
+++ b/post/cpu/mpc8xx/ether.c
@@ -67,8 +67,6 @@
 static int ctlr_list[][2] = { };
 #endif
 
-#define CTRL_LIST_SIZE (sizeof(ctlr_list) / sizeof(ctlr_list[0]))
-
 static struct {
 	void (*init) (int index);
 	void (*halt) (int index);
@@ -618,7 +616,7 @@
 	ctlr_proc[CTLR_SCC].send = scc_send;
 	ctlr_proc[CTLR_SCC].recv = scc_recv;
 
-	for (i = 0; i < CTRL_LIST_SIZE; i++) {
+	for (i = 0; i < ARRAY_SIZE(ctlr_list); i++) {
 		if (test_ctlr (ctlr_list[i][0], ctlr_list[i][1]) != 0) {
 			res = -1;
 		}