btrfs: drop unused parameter from btrfs_release_path

parameter tree root it's not used since commit
5f39d397dfbe140a14edecd4e73c34ce23c4f9ee ("Btrfs: Create extent_buffer
interface for large blocksizes")

Signed-off-by: David Sterba <dsterba@suse.cz>
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index ffb48d6c..d11fc65 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -1396,7 +1396,7 @@
 		}
 		ret = copy_to_sk(root, path, &key, sk, args->buf,
 				 &sk_offset, &num_found);
-		btrfs_release_path(root, path);
+		btrfs_release_path(path);
 		if (ret || num_found >= sk->nr_items)
 			break;
 
@@ -1503,7 +1503,7 @@
 		if (key.offset == BTRFS_FIRST_FREE_OBJECTID)
 			break;
 
-		btrfs_release_path(root, path);
+		btrfs_release_path(path);
 		key.objectid = key.offset;
 		key.offset = (u64)-1;
 		dirid = key.objectid;
@@ -1982,7 +1982,7 @@
 				datal = btrfs_file_extent_ram_bytes(leaf,
 								    extent);
 			}
-			btrfs_release_path(root, path);
+			btrfs_release_path(path);
 
 			if (key.offset + datal <= off ||
 			    key.offset >= off+len)
@@ -2092,7 +2092,7 @@
 			}
 
 			btrfs_mark_buffer_dirty(leaf);
-			btrfs_release_path(root, path);
+			btrfs_release_path(path);
 
 			inode->i_mtime = inode->i_ctime = CURRENT_TIME;
 
@@ -2113,12 +2113,12 @@
 			btrfs_end_transaction(trans, root);
 		}
 next:
-		btrfs_release_path(root, path);
+		btrfs_release_path(path);
 		key.offset++;
 	}
 	ret = 0;
 out:
-	btrfs_release_path(root, path);
+	btrfs_release_path(path);
 	unlock_extent(&BTRFS_I(src)->io_tree, off, off+len, GFP_NOFS);
 out_unlock:
 	mutex_unlock(&src->i_mutex);