ASoC: Add register write logging for WM8994

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: Liam Girdwood <lrg@slimlogic.co.uk>
diff --git a/sound/soc/codecs/wm8994.c b/sound/soc/codecs/wm8994.c
index f04a116..c6b3f1e 100644
--- a/sound/soc/codecs/wm8994.c
+++ b/sound/soc/codecs/wm8994.c
@@ -1710,6 +1710,8 @@
 	if (!wm8994_volatile(reg))
 		wm8994->reg_cache[reg] = value;
 
+	dev_dbg(codec->dev, "0x%x = 0x%x\n", reg, value);
+
 	return wm8994_reg_write(codec->control_data, reg, value);
 }