Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/perf/ui/gtk/helpline.c b/tools/perf/ui/gtk/helpline.c
index fbf1ea9..e40a006 100644
--- a/tools/perf/ui/gtk/helpline.c
+++ b/tools/perf/ui/gtk/helpline.c
@@ -1,11 +1,11 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <stdio.h>
 #include <string.h>
+#include <linux/kernel.h>
 
 #include "gtk.h"
 #include "../ui.h"
 #include "../helpline.h"
-#include "../../util/debug.h"
 
 static void gtk_helpline_pop(void)
 {