SUNRPC: pass buffer size to svc_addsock()

Adjust the synopsis of svc_addsock() to pass in the size of the output
buffer.  Add a documenting comment.

This is a cosmetic change for now.  A subsequent patch will make sure
the buffer length is passed to one_sock_name(), where the length will
actually be useful.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 6a1cd90..1f1c215 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -943,7 +943,7 @@
 	if (err != 0)
 		goto out;
 
-	err = svc_addsock(nfsd_serv, fd, buf);
+	err = svc_addsock(nfsd_serv, fd, buf, SIMPLE_TRANSACTION_LIMIT);
 	if (err < 0)
 		lockd_down();