Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/x86/include/asm/time.h b/arch/x86/include/asm/time.h
index cef818b..8ac563a 100644
--- a/arch/x86/include/asm/time.h
+++ b/arch/x86/include/asm/time.h
@@ -7,6 +7,7 @@
 
 extern void hpet_time_init(void);
 extern void time_init(void);
+extern bool pit_timer_init(void);
 
 extern struct clock_event_device *global_clock_event;