NFS: Fix the 'proto=' mount option

Currently, if you have a server mounted using networking protocol, you
cannot specify a different value using the 'proto=' option on another
mountpoint.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index d15c948..b5ba5f7 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -29,6 +29,7 @@
 
 	struct rpc_clnt *	cl_rpcclient;
 	const struct nfs_rpc_ops *rpc_ops;	/* NFS protocol vector */
+	int			cl_proto;	/* Network transport protocol */
 
 #ifdef CONFIG_NFS_V4
 	u64			cl_clientid;	/* constant */