btrfs: simplify return variables in btrfs_drop_subtree()

There's another return variable wret that is only passed to ret on
error, we can simply use ret.

Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

Author: asj

fs/btrfs/extent-tree.c

@@ -6099,7 +6099,6 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
 	int level;
 	int parent_level;
 	int ret = 0;
-	int wret;
 
 	BUG_ON(btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID);
 
@@ -6135,17 +6134,16 @@ int btrfs_drop_subtree(struct btrfs_trans_handle *trans,
 	wc->reada_count = BTRFS_NODEPTRS_PER_BLOCK(fs_info);
 
 	while (1) {
-		wret = walk_down_tree(trans, root, path, wc);
-		if (wret < 0) {
-			ret = wret;
+		ret = walk_down_tree(trans, root, path, wc);
+		if (ret < 0)
 			break;
-		}
 
-		wret = walk_up_tree(trans, root, path, wc, parent_level);
-		if (wret < 0)
-			ret = wret;
-		if (wret != 0)
+		ret = walk_up_tree(trans, root, path, wc, parent_level);
+		if (ret) {
+			if (ret > 0)
+				ret = 0;
 			break;
+		}
 	}
 
 	kfree(wc);