soundwire: fix SPDX license for header files

No C++ comments in .h files

Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/soundwire/bus.h

@@ -1,5 +1,5 @@
-// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
-// Copyright(c) 2015-17 Intel Corporation.
+/* SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause) */
+/* Copyright(c) 2015-17 Intel Corporation. */
 
 #ifndef __SDW_BUS_H
 #define __SDW_BUS_H