ASoC: sgtl5000: add ADC mute control

This control mute/unmute the ADC input of SGTL5000
using its CHIP_ANA_CTRL register.

Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@toradex.com>
Reviewed-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Igor Opaniuk <igor.opaniuk@toradex.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Link: https://lore.kernel.org/r/20190719100524.23300-5-oleksandr.suvorov@toradex.com
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/sgtl5000.c

@@ -720,6 +720,7 @@ static const struct snd_kcontrol_new sgtl5000_snd_controls[] = {
 			SGTL5000_CHIP_ANA_ADC_CTRL,
 			8, 1, 0, capture_6db_attenuate),
 	SOC_SINGLE("Capture ZC Switch", SGTL5000_CHIP_ANA_CTRL, 1, 1, 0),
+	SOC_SINGLE("Capture Switch", SGTL5000_CHIP_ANA_CTRL, 0, 1, 1),
 
 	SOC_DOUBLE_TLV("Headphone Playback Volume",
 			SGTL5000_CHIP_ANA_HP_CTRL,