Btrfs: simplify iteration codes

Merge list_for_each* and list_entry to list_for_each_entry*

Signed-off-by: Qinghuang Feng <qhfeng.kernel@gmail.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c
index 8a08f94..919172de 100644
--- a/fs/btrfs/transaction.c
+++ b/fs/btrfs/transaction.c
@@ -852,11 +852,9 @@
 {
 	struct btrfs_pending_snapshot *pending;
 	struct list_head *head = &trans->transaction->pending_snapshots;
-	struct list_head *cur;
 	int ret;
 
-	list_for_each(cur, head) {
-		pending = list_entry(cur, struct btrfs_pending_snapshot, list);
+	list_for_each_entry(pending, head, list) {
 		ret = create_pending_snapshot(trans, fs_info, pending);
 		BUG_ON(ret);
 	}