Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/batman-adv/send.h b/net/batman-adv/send.h
index 64cce07..5fc0fd1 100644
--- a/net/batman-adv/send.h
+++ b/net/batman-adv/send.h
@@ -1,19 +1,7 @@
 /* SPDX-License-Identifier: GPL-2.0 */
-/* Copyright (C) 2007-2018  B.A.T.M.A.N. contributors:
+/* Copyright (C) 2007-2019  B.A.T.M.A.N. contributors:
  *
  * Marek Lindner, Simon Wunderlich
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of version 2 of the GNU General Public
- * License as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful, but
- * WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, see <http://www.gnu.org/licenses/>.
  */
 
 #ifndef _NET_BATMAN_ADV_SEND_H_
@@ -22,12 +10,11 @@
 #include "main.h"
 
 #include <linux/compiler.h>
+#include <linux/skbuff.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
 #include <uapi/linux/batadv_packet.h>
 
-struct sk_buff;
-
 void batadv_forw_packet_free(struct batadv_forw_packet *forw_packet,
 			     bool dropped);
 struct batadv_forw_packet *