NFS: switch NFSROOT to use new rpcbind client

It is arguable whether NFSROOT will support IPv6, and thus whether
rpcb_getport_external needs to support rpcbind versions greater than 2.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

fs/nfs/nfsroot.c

@@ -428,7 +428,7 @@ static int __init root_nfs_getport(int program, int version, int proto)
 	printk(KERN_NOTICE "Looking up port of RPC %d/%d on %u.%u.%u.%u\n",
 		program, version, NIPQUAD(servaddr));
 	set_sockaddr(&sin, servaddr, 0);
-	return rpc_getport_external(&sin, program, version, proto);
+	return rpcb_getport_external(&sin, program, version, proto);
 }