Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/mm/percpu-vm.c b/mm/percpu-vm.c
index d8078de..a2b395a 100644
--- a/mm/percpu-vm.c
+++ b/mm/percpu-vm.c
@@ -1,11 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * mm/percpu-vm.c - vmalloc area based chunk allocation
  *
  * Copyright (C) 2010		SUSE Linux Products GmbH
  * Copyright (C) 2010		Tejun Heo <tj@kernel.org>
  *
- * This file is released under the GPLv2.
- *
  * Chunks are mapped into vmalloc areas and populated page by page.
  * This is the default chunk allocator.
  */