Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/perf/util/perf-hooks.c b/tools/perf/util/perf-hooks.c
index 4f3aa8d..7a0ab35 100644
--- a/tools/perf/util/perf-hooks.c
+++ b/tools/perf/util/perf-hooks.c
@@ -8,10 +8,10 @@
 
 #include <errno.h>
 #include <stdlib.h>
+#include <string.h>
 #include <setjmp.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
-#include "util/util.h"
 #include "util/debug.h"
 #include "util/perf-hooks.h"