Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/net/can/spi/Makefile b/drivers/net/can/spi/Makefile
index f59fa37..f115b2c 100644
--- a/drivers/net/can/spi/Makefile
+++ b/drivers/net/can/spi/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 #
 #  Makefile for the Linux Controller Area Network SPI drivers.
 #