Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/kernel/time/timeconst.bc b/kernel/time/timeconst.bc
index f83bbb8..7ed0e0f 100644
--- a/kernel/time/timeconst.bc
+++ b/kernel/time/timeconst.bc
@@ -1,3 +1,5 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
 scale=0
 
 define gcd(a,b) {