ASoC: sta32x: Fix cache sync

codec->control_data contains a pointer to the regmap struct of the device, not
to the device private data. Use snd_soc_codec_get_drvdata() instead.

The issue was introduced in commit 29fdf4fb ("ASoC: sta32x: Convert to
regmap").

Fixes: 29fdf4fb (ASoC: sta32x: Convert to regmap)
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Mark Brown <broonie@linaro.org>
Cc: stable@vger.kernel.org

sound/soc/codecs/sta32x.c

@@ -331,7 +331,7 @@ static int sta32x_sync_coef_shadow(struct snd_soc_codec *codec)
 
 static int sta32x_cache_sync(struct snd_soc_codec *codec)
 {
-	struct sta32x_priv *sta32x = codec->control_data;
+	struct sta32x_priv *sta32x = snd_soc_codec_get_drvdata(codec);
 	unsigned int mute;
 	int rc;