ASoC: intel: constify snd_pcm_ops structures

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

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
diff --git a/sound/soc/intel/baytrail/sst-baytrail-pcm.c b/sound/soc/intel/baytrail/sst-baytrail-pcm.c
index 84cb568..c545293 100644
--- a/sound/soc/intel/baytrail/sst-baytrail-pcm.c
+++ b/sound/soc/intel/baytrail/sst-baytrail-pcm.c
@@ -309,7 +309,7 @@
 	return snd_pcm_lib_default_mmap(substream, vma);
 }
 
-static struct snd_pcm_ops sst_byt_pcm_ops = {
+static const struct snd_pcm_ops sst_byt_pcm_ops = {
 	.open		= sst_byt_pcm_open,
 	.close		= sst_byt_pcm_close,
 	.ioctl		= snd_pcm_lib_ioctl,