Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/Kconfig.freezer b/kernel/Kconfig.freezer
index a3bb4cb..68646fe 100644
--- a/kernel/Kconfig.freezer
+++ b/kernel/Kconfig.freezer
@@ -1,2 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config FREEZER
 	def_bool PM_SLEEP || CGROUP_FREEZER