SUNRPC: Add address family field to svc_serv data structure

Introduce and initialize an address family field in the svc_serv structure.

This field will determine what family to use for the service's listener
sockets and what families are advertised via the local rpcbind daemon.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index f447f4b..6a09760 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -105,7 +105,8 @@
 	mutex_lock(&nfs_callback_mutex);
 	if (nfs_callback_info.users++ || nfs_callback_info.task != NULL)
 		goto out;
-	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
+	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE,
+				AF_INET, NULL);
 	ret = -ENOMEM;
 	if (!serv)
 		goto out_err;