ASoC: nuc900: 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: NArvind Yadav <arvind.yadav.cs@gmail.com>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/nuc900/nuc900-pcm.c

@@ -271,7 +271,7 @@ static int nuc900_dma_mmap(struct snd_pcm_substream *substream,
 			   runtime->dma_addr, runtime->dma_bytes);
 }
 
-static struct snd_pcm_ops nuc900_dma_ops = {
+static const struct snd_pcm_ops nuc900_dma_ops = {
 	.open		= nuc900_dma_open,
 	.close		= nuc900_dma_close,
 	.ioctl		= snd_pcm_lib_ioctl,