configfs: Add permission and ownership to configfs objects.

configfs always made item and attribute ownership root.root and
permissions based on a umask of 022.  Add ->setattr() to allow
chown(2)/chmod(2), and persist the changes for the lifetime of the
items and attributes.

Signed-off-by: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>

fs/configfs/symlink.c

@@ -277,5 +277,6 @@ struct inode_operations configfs_symlink_inode_operations = {
 	.follow_link = configfs_follow_link,
 	.readlink = generic_readlink,
 	.put_link = configfs_put_link,
+	.setattr = configfs_setattr,
 };