Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/mips/ath79/common.h b/arch/mips/ath79/common.h
index 870c6b2..47fb66d 100644
--- a/arch/mips/ath79/common.h
+++ b/arch/mips/ath79/common.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  *  Atheros AR71XX/AR724X/AR913X common definitions
  *
@@ -5,10 +6,6 @@
  *  Copyright (C) 2008 Imre Kaloz <kaloz@openwrt.org>
  *
  *  Parts of this file are based on Atheros' 2.6.15 BSP
- *
- *  This program is free software; you can redistribute it and/or modify it
- *  under the terms of the GNU General Public License version 2 as published
- *  by the Free Software Foundation.
  */
 
 #ifndef __ATH79_COMMON_H
@@ -19,11 +16,6 @@
 #define ATH79_MEM_SIZE_MIN	(2 * 1024 * 1024)
 #define ATH79_MEM_SIZE_MAX	(256 * 1024 * 1024)
 
-void ath79_clocks_init(void);
-unsigned long ath79_get_sys_clk_rate(const char *id);
-
 void ath79_ddr_ctrl_init(void);
 
-void ath79_gpio_init(void);
-
 #endif /* __ATH79_COMMON_H */