Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/lib/zalloc.c b/tools/lib/zalloc.c
new file mode 100644
index 0000000..9c856d5
--- /dev/null
+++ b/tools/lib/zalloc.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: LGPL-2.1
+
+#include <stdlib.h>
+#include <linux/zalloc.h>
+
+void *zalloc(size_t size)
+{
+	return calloc(1, size);
+}
+
+void __zfree(void **ptr)
+{
+	free(*ptr);
+	*ptr = NULL;
+}