Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/sound/isa/Kconfig b/sound/isa/Kconfig
index d7db1ee..b690ed9 100644
--- a/sound/isa/Kconfig
+++ b/sound/isa/Kconfig
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0-only
 # ALSA ISA drivers
 
 config SND_WSS_LIB