Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/mips/loongson64/common/serial.c b/arch/mips/loongson64/common/serial.c
index ffefc1c..98c3a7f 100644
--- a/arch/mips/loongson64/common/serial.c
+++ b/arch/mips/loongson64/common/serial.c
@@ -110,7 +110,7 @@
 }
 module_init(serial_init);
 
-static void __init serial_exit(void)
+static void __exit serial_exit(void)
 {
 	platform_device_unregister(&uart8250_device);
 }