btrfs: remove unnecessary set_nlink() in btrfs_create_subvol_root()

btrfs_new_inode() already returns an inode with nlink set to 1 (via
inode_init_always()). Get rid of the unnecessary set.
Reviewed-by: NSweet Tea Dorminy <sweettea-kernel@dorminy.me>
Signed-off-by: NOmar Sandoval <osandov@fb.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/inode.c

@@ -8777,7 +8777,6 @@ int btrfs_create_subvol_root(struct btrfs_trans_handle *trans,
 	inode->i_op = &btrfs_dir_inode_operations;
 	inode->i_fop = &btrfs_dir_file_operations;
 
-	set_nlink(inode, 1);
 	unlock_new_inode(inode);
 
 	err = btrfs_subvol_inherit_props(trans, new_root, parent_root);