Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index 4a585cb..c684768 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -94,6 +94,9 @@
 	return crashing_cpu >= 0;
 }
 
+void relocate_new_kernel(unsigned long indirection_page, unsigned long reboot_code_buffer,
+			 unsigned long start_address) __noreturn;
+
 #ifdef CONFIG_KEXEC_FILE
 extern const struct kexec_file_ops kexec_elf64_ops;