constify dentry_operations: NFS

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 672368f..78bf72f 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -899,7 +899,7 @@
 	iput(inode);
 }
 
-struct dentry_operations nfs_dentry_operations = {
+const struct dentry_operations nfs_dentry_operations = {
 	.d_revalidate	= nfs_lookup_revalidate,
 	.d_delete	= nfs_dentry_delete,
 	.d_iput		= nfs_dentry_iput,
@@ -967,7 +967,7 @@
 #ifdef CONFIG_NFS_V4
 static int nfs_open_revalidate(struct dentry *, struct nameidata *);
 
-struct dentry_operations nfs4_dentry_operations = {
+const struct dentry_operations nfs4_dentry_operations = {
 	.d_revalidate	= nfs_open_revalidate,
 	.d_delete	= nfs_dentry_delete,
 	.d_iput		= nfs_dentry_iput,