Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/riscv/kernel/time.c b/arch/riscv/kernel/time.c
index 1911c8f..6a53c02 100644
--- a/arch/riscv/kernel/time.c
+++ b/arch/riscv/kernel/time.c
@@ -1,22 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (C) 2012 Regents of the University of California
  * Copyright (C) 2017 SiFive
- *
- *   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, version 2.
- *
- *   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.
  */
 
 #include <linux/clocksource.h>
 #include <linux/delay.h>
 #include <asm/sbi.h>
+#include <asm/processor.h>
 
 unsigned long riscv_timebase;
+EXPORT_SYMBOL_GPL(riscv_timebase);
 
 void __init time_init(void)
 {
@@ -26,6 +20,7 @@
 	cpu = of_find_node_by_path("/cpus");
 	if (!cpu || of_property_read_u32(cpu, "timebase-frequency", &prop))
 		panic(KERN_WARNING "RISC-V system with no 'timebase-frequency' in DTS\n");
+	of_node_put(cpu);
 	riscv_timebase = prop;
 
 	lpj_fine = riscv_timebase / HZ;