asoc: Update file header to GPL-2.0-only

Update file header to GPL-2.0-only.

Change-Id: Ic1542a3209a5fe73c937a5b36491ede4a451936d
Signed-off-by: Meng Wang <mengw@codeaurora.org>
diff --git a/asoc/codecs/wcd9335_irq.h b/asoc/codecs/wcd9335_irq.h
index ae81a1a..39a223d 100644
--- a/asoc/codecs/wcd9335_irq.h
+++ b/asoc/codecs/wcd9335_irq.h
@@ -1,4 +1,4 @@
-/* SPDX-License-Identifier: GPL-2.0 */
+/* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * Copyright (c) 2017, The Linux Foundation. All rights reserved.
  */