ASoC: wm8731: Replace w->codec snd_soc_dapm_to_codec(w->dapm)

The codec field of the snd_soc_widget struct is eventually going to be
removed, use snd_soc_dapm_to_codec(w->dapm) instead.
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm8731.c

@@ -217,7 +217,8 @@ SND_SOC_DAPM_INPUT("LLINEIN"),
 static int wm8731_check_osc(struct snd_soc_dapm_widget *source,
 			    struct snd_soc_dapm_widget *sink)
 {
-	struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(source->codec);
+	struct snd_soc_codec *codec = snd_soc_dapm_to_codec(source->dapm);
+	struct wm8731_priv *wm8731 = snd_soc_codec_get_drvdata(codec);
 
 	return wm8731->sysclk_type == WM8731_SYSCLK_XTAL;
 }