ASoC: Fix type for snd_soc_volatile_register()

We generally refer to registers as unsigned ints (including in the
underlying CODEC driver operation).

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/include/sound/soc.h b/include/sound/soc.h
index c184f84..1355ef0 100644
--- a/include/sound/soc.h
+++ b/include/sound/soc.h
@@ -267,7 +267,8 @@
 		const struct snd_soc_codec_driver *codec_drv,
 		struct snd_soc_dai_driver *dai_drv, int num_dai);
 void snd_soc_unregister_codec(struct device *dev);
-int snd_soc_codec_volatile_register(struct snd_soc_codec *codec, int reg);
+int snd_soc_codec_volatile_register(struct snd_soc_codec *codec,
+				    unsigned int reg);
 int snd_soc_codec_set_cache_io(struct snd_soc_codec *codec,
 			       int addr_bits, int data_bits,
 			       enum snd_soc_control_type control);