ASoC: cs42l51: add additional ADC volume controls

Add volume controls for:
- Analog programmable gain amplifier (PGA) (-3 .. +12 dB)
- ADC attenuator (0 .. -96 dB)

Signed-off-by: Guillermo Rodríguez <guille.rodriguez@gmail.com>
Acked-by: David Rhodes <David.rhodes@cirrus.com>
Link: https://lore.kernel.org/r/20200918134317.22574-1-guille.rodriguez@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>