ASoC: wm8994: Only enable extra BCLK cycles when required

Rather than always assuming the maximum possible BCLK rate will be
required generate BCLKs for stereo if either one or two channels is
enabled. In order to support this we also need to ensure that only
the relevant channels are enabled.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

sound/soc/codecs/wm8994.h

@@ -77,6 +77,7 @@ struct wm8994_priv {
 	int sysclk_rate[2];
 	int mclk[2];
 	int aifclk[2];
+	int channels[2];
 	struct wm8994_fll_config fll[2], fll_suspend[2];
 	struct completion fll_locked[2];
 	bool fll_locked_irq;