Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/x86/include/asm/crash.h b/arch/x86/include/asm/crash.h
index a7adb2b..0acf5ee 100644
--- a/arch/x86/include/asm/crash.h
+++ b/arch/x86/include/asm/crash.h
@@ -6,5 +6,6 @@
 int crash_copy_backup_region(struct kimage *image);
 int crash_setup_memmap_entries(struct kimage *image,
 		struct boot_params *params);
+void crash_smp_send_stop(void);
 
 #endif /* _ASM_X86_CRASH_H */