codecs/rt5672: Add hardware volume-control support

codecs/rt5672: Add hardware volume-control support

For the speaker and DMICs configs this uses "DAC1 Playback Volume"
resp. "ADC Capture Volume" as main mixer elements, since there are
no other volume-controls in their paths.

For the (analog) headset-mic and headphones this used the analog
"IN1 Boost" resp. "HP Playback Volume" controls as main mixer elements
while using the  "ADC Capture Volume" resp. "DAC1 Playback Volume"
(which have the mute switches) as master mixer elements.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>