staging: greybus: audio: constify snd_soc_dai_ops structures

snd_soc_dai_ops are not supposed to change at runtime. All functions
working with snd_soc_dai_ops provided by <sound/soc-dai.h> work with
const snd_soc_dai_ops. So mark the non-const structs as const.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Acked-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/greybus/audio_codec.c

@@ -674,7 +674,7 @@ static int gbcodec_mute_stream(struct snd_soc_dai *dai, int mute, int stream)
 	return ret;
 }
 
-static struct snd_soc_dai_ops gbcodec_dai_ops = {
+static const struct snd_soc_dai_ops gbcodec_dai_ops = {
 	.startup = gbcodec_startup,
 	.shutdown = gbcodec_shutdown,
 	.hw_params = gbcodec_hw_params,