ASoC: Constify struct snd_soc_codec_driver

Allow the CODEC driver structure to be marked const by making all
the APIs that use it do so.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/sound/soc/soc-core.c b/sound/soc/soc-core.c
index e9aa9ce..78a0101 100644
--- a/sound/soc/soc-core.c
+++ b/sound/soc/soc-core.c
@@ -3491,8 +3491,9 @@
  * @codec: codec to register
  */
 int snd_soc_register_codec(struct device *dev,
-		struct snd_soc_codec_driver *codec_drv,
-		struct snd_soc_dai_driver *dai_drv, int num_dai)
+			   const struct snd_soc_codec_driver *codec_drv,
+			   struct snd_soc_dai_driver *dai_drv,
+			   int num_dai)
 {
 	size_t reg_size;
 	struct snd_soc_codec *codec;