Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/net/wireless/quantenna/Makefile b/drivers/net/wireless/quantenna/Makefile
index baebfbd..cea83d1 100644
--- a/drivers/net/wireless/quantenna/Makefile
+++ b/drivers/net/wireless/quantenna/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 #
 # Copyright (c) 2015-2016 Quantenna Communications, Inc.
 # All rights reserved.