Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/tools/perf/scripts/perl/rw-by-pid.pl b/tools/perf/scripts/perl/rw-by-pid.pl
index 9db23c9..4956982 100644
--- a/tools/perf/scripts/perl/rw-by-pid.pl
+++ b/tools/perf/scripts/perl/rw-by-pid.pl
@@ -1,6 +1,6 @@
 #!/usr/bin/perl -w
+# SPDX-License-Identifier: GPL-2.0-only
 # (c) 2009, Tom Zanussi <tzanussi@gmail.com>
-# Licensed under the terms of the GNU GPL License version 2
 
 # Display r/w activity for all processes