ASoC: Enable ASoC register map dump for some regmap CODECs

It's still useful to be able to poke around in the register map at
runtime.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index 71472b6..93d27b6 100644
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -3815,12 +3815,20 @@
 	return 0;
 }
 
+static int wm8994_soc_volatile(struct snd_soc_codec *codec,
+			       unsigned int reg)
+{
+	return true;
+}
+
 static struct snd_soc_codec_driver soc_codec_dev_wm8994 = {
 	.probe =	wm8994_codec_probe,
 	.remove =	wm8994_codec_remove,
 	.suspend =	wm8994_suspend,
 	.resume =	wm8994_resume,
 	.set_bias_level = wm8994_set_bias_level,
+	.reg_cache_size	= WM8994_MAX_REGISTER,
+	.volatile_register = wm8994_soc_volatile,
 };
 
 static int __devinit wm8994_probe(struct platform_device *pdev)