Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/net/hamradio/Kconfig b/drivers/net/hamradio/Kconfig
index bf5e596..8e05b5c 100644
--- a/drivers/net/hamradio/Kconfig
+++ b/drivers/net/hamradio/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config MKISS
 	tristate "Serial port KISS driver"
 	depends on AX25 && TTY