Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/lib/xz/Kconfig b/lib/xz/Kconfig
index 12d2d77..2252874 100644
--- a/lib/xz/Kconfig
+++ b/lib/xz/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config XZ_DEC
 	tristate "XZ decompression support"
 	select CRC32