ASoC: codecs: jz4740: Use SPDX license notifier

Add license information as a standard SPDX license notifier instead of
custom text.
Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/jz4740.c

-/*
- * Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- *  You should have received a copy of the  GNU General Public License along
- *  with this program; if not, write  to the Free Software Foundation, Inc.,
- *  675 Mass Ave, Cambridge, MA 02139, USA.
- *
- */
+// SPDX-License-Identifier: GPL-2.0
+//
+// JZ4740 CODEC driver
+//
+// Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
 
 #include <linux/kernel.h>
 #include <linux/module.h>