btrfs: delayed-ref: pass delayed_refs directly to btrfs_select_ref_head

Since trans is only used for referring to delayed_refs, there is no need
to pass it instead of delayed_refs to btrfs_select_ref_head().  No
functional change.

Signed-off-by: Lu Fengqi <lufq.fnst@cn.fujitsu.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index c4a1e8f..5141fe6 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -2511,7 +2511,7 @@ static struct btrfs_delayed_ref_head *btrfs_obtain_ref_head(
 	int ret;
 
 	spin_lock(&delayed_refs->lock);
-	head = btrfs_select_ref_head(trans);
+	head = btrfs_select_ref_head(delayed_refs);
 	if (!head) {
 		spin_unlock(&delayed_refs->lock);
 		return head;