Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/nfs/flexfilelayout/Makefile b/fs/nfs/flexfilelayout/Makefile
index 1d2c9f6..49f0342 100644
--- a/fs/nfs/flexfilelayout/Makefile
+++ b/fs/nfs/flexfilelayout/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 # Makefile for the pNFS Flexfile Layout Driver kernel module
 #