ASoC: rt5670: Enable MCLK detection

There is a power saving mechanism in rt5670. It will turn off some
unused power when MCLK is not present. We call that "MCLK detection"
and it should be enabled by default.

Signed-off-by: Bard Liao <bardliao@realtek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/rt5670.h

@@ -1914,6 +1914,7 @@ enum {
 #define RT5670_IF1_ADC1_IN2_SFT			11
 #define RT5670_IF1_ADC2_IN1_SEL			(0x1 << 10)
 #define RT5670_IF1_ADC2_IN1_SFT			10
+#define RT5670_MCLK_DET				(0x1 << 3)
 
 /* General Control2 (0xfb) */
 #define RT5670_RXDC_SRC_MASK			(0x1 << 7)