Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/net/nsh/Kconfig b/net/nsh/Kconfig
index bafc3dd..19af948 100644
--- a/net/nsh/Kconfig
+++ b/net/nsh/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 menuconfig NET_NSH
 	tristate "Network Service Header (NSH) protocol"
 	default n