NFSv4: Ensure DELEGRETURN returns attributes

Upon return of a write delegation, the server will almost always bump the
 change attribute. Ensure that we pick up that change so that we don't
 invalidate our data cache unnecessarily.

 Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

include/linux/nfs_xdr.h

@@ -220,6 +220,12 @@ struct nfs_lockt_res {
 struct nfs4_delegreturnargs {
 	const struct nfs_fh *fhandle;
 	const nfs4_stateid *stateid;
+	const u32 * bitmask;
+};
+
+struct nfs4_delegreturnres {
+	struct nfs_fattr * fattr;
+	const struct nfs_server *server;
 };
 
 /*