Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/drivers/hid/hid-aureal.c b/drivers/hid/hid-aureal.c
index 3280aff..ac8946f 100644
--- a/drivers/hid/hid-aureal.c
+++ b/drivers/hid/hid-aureal.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  *  HID driver for Aureal Cy se W-01RN USB_V3.1 devices
  *