nfsd: constify nfsd4_callback_ops structure

The nfsd4_callback_ops structure is never modified, so declare it as const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index e7f50c4..081709c3 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -1143,7 +1143,7 @@
 }
 
 void nfsd4_init_cb(struct nfsd4_callback *cb, struct nfs4_client *clp,
-		struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
+		const struct nfsd4_callback_ops *ops, enum nfsd4_cb_op op)
 {
 	cb->cb_clp = clp;
 	cb->cb_msg.rpc_proc = &nfs4_cb_procedures[op];