Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 20291c2..ab5add0 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *	Extension Header handling for IPv6
  *	Linux INET6 implementation
@@ -6,11 +7,6 @@
  *	Pedro Roque		<roque@di.fc.ul.pt>
  *	Andi Kleen		<ak@muc.de>
  *	Alexey Kuznetsov	<kuznet@ms2.inr.ac.ru>
- *
- *	This program is free software; you can redistribute it and/or
- *      modify it under the terms of the GNU General Public License
- *      as published by the Free Software Foundation; either version
- *      2 of the License, or (at your option) any later version.
  */
 
 /* Changes: