SUNRPC: constify the rpc_program

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index eda4cde4..cdb121d 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -145,7 +145,7 @@
 extern void nfs_umount(const struct nfs_mount_request *info);
 
 /* client.c */
-extern struct rpc_program nfs_program;
+extern const struct rpc_program nfs_program;
 
 extern void nfs_cleanup_cb_ident_idr(void);
 extern void nfs_put_client(struct nfs_client *);