Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/net/wireless/broadcom/Kconfig b/drivers/net/wireless/broadcom/Kconfig
index eebe286..bb1cb40 100644
--- a/drivers/net/wireless/broadcom/Kconfig
+++ b/drivers/net/wireless/broadcom/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 config WLAN_VENDOR_BROADCOM
 	bool "Broadcom devices"
 	default y