Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/perf/util/expr.y b/tools/perf/util/expr.y
index 432b856..f9a20a3 100644
--- a/tools/perf/util/expr.y
+++ b/tools/perf/util/expr.y
@@ -2,9 +2,11 @@
 %{
 #include "util.h"
 #include "util/debug.h"
+#include <stdlib.h> // strtod()
 #define IN_EXPR_Y 1
 #include "expr.h"
 #include "smt.h"
+#include <assert.h>
 #include <string.h>
 
 #define MAXIDLEN 256