ASoC: Fix incorrect parameter to snd_soc_codec_volatile_register

We need to pass the register index and not the register value.
This patch depends on my previous patch "ASoC: Delegate to hw
specific read for volatile registers".
Signed-off-by: Dimitris Papastamos <dp@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/soc-cache.c

@@ -177,7 +177,7 @@ static int snd_soc_8_8_write(struct snd_soc_codec *codec, unsigned int reg,
 	data[0] = reg;
 	data[1] = value & 0xff;
 
-	if (!snd_soc_codec_volatile_register(codec, value) &&
+	if (!snd_soc_codec_volatile_register(codec, reg) &&
 		reg < codec->driver->reg_cache_size)
 			cache[reg] = value;