md: change ITERATE_RDEV to rdev_for_each

As this is more in line with common practice in the kernel.  Also swap the
args around to be more like list_for_each.

Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
index d6f1288..017f581 100644
--- a/drivers/md/raid10.c
+++ b/drivers/md/raid10.c
@@ -2026,7 +2026,7 @@
 		goto out_free_conf;
 	}
 
-	ITERATE_RDEV(mddev, rdev, tmp) {
+	rdev_for_each(rdev, tmp, mddev) {
 		disk_idx = rdev->raid_disk;
 		if (disk_idx >= mddev->raid_disks
 		    || disk_idx < 0)