Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/include/linux/sunrpc/svcauth.h b/include/linux/sunrpc/svcauth.h
index 04e404a..3e53a6e 100644
--- a/include/linux/sunrpc/svcauth.h
+++ b/include/linux/sunrpc/svcauth.h
@@ -82,6 +82,7 @@
 	struct hlist_node	hash;
 	char			*name;
 	struct auth_ops		*flavour;
+	struct rcu_head		rcu_head;
 };
 
 /*