ASoC: rockchip: constify snd_soc_dai_ops structures

These snd_soc_dai_ops structures are only stored in the ops field of
a snd_soc_dai_driver structure, which is const.  Thus, the
snd_soc_dai_ops structures can be const too.

Done with the help of Coccinelle.
Signed-off-by: NJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: NMark Brown <broonie@kernel.org>

sound/soc/rockchip/rockchip_pdm.c

@@ -249,7 +249,7 @@ static int rockchip_pdm_dai_probe(struct snd_soc_dai *dai)
 	return 0;
 }
 
-static struct snd_soc_dai_ops rockchip_pdm_dai_ops = {
+static const struct snd_soc_dai_ops rockchip_pdm_dai_ops = {
 	.set_fmt = rockchip_pdm_set_fmt,
 	.trigger = rockchip_pdm_trigger,
 	.hw_params = rockchip_pdm_hw_params,