ASoC: wm8962: Export DAC/ADC monomix switches

This allows solutions like ALSA UCM to utilize hardware mono downmix
for cases where mono output to a single speaker is desired only in
specific situations (like on a mobile phone).
Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/3662154.EqNIRYjrc8@pliszkaSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/codecs/wm8962.c

@@ -1702,6 +1702,8 @@ SOC_DOUBLE_R_TLV("Digital Playback Volume", WM8962_LEFT_DAC_VOLUME,
 SOC_SINGLE("DAC High Performance Switch", WM8962_ADC_DAC_CONTROL_2, 0, 1, 0),
 SOC_SINGLE("DAC L/R Swap Switch", WM8962_AUDIO_INTERFACE_0, 5, 1, 0),
 SOC_SINGLE("ADC L/R Swap Switch", WM8962_AUDIO_INTERFACE_0, 8, 1, 0),
+SOC_SINGLE("DAC Monomix Switch", WM8962_DAC_DSP_MIXING_1, WM8962_DAC_MONOMIX_SHIFT, 1, 0),
+SOC_SINGLE("ADC Monomix Switch", WM8962_THREED1, WM8962_ADC_MONOMIX_SHIFT, 1, 0),
 
 SOC_SINGLE("ADC High Performance Switch", WM8962_ADDITIONAL_CONTROL_1,
 	   5, 1, 0),