cht-bsw-rt5672: Boost ADC volume a bit

cht-bsw-rt5672: Boost ADC volume a bit

Both the DMICs and the headset mic are quite soft, even with the 20 dB
IN1 boost we already congfigure for the headset.

This commit sets the ADC Boost gain (range 0-3) to 1 = 12 dB, which makes
the volume a lot better. The next step of the ADC Boost gain setting is
24 dB which is a bit too much.

This has been tested with both the builtin DMIC and with a headset mic
on the following devices:

Lenovo Miix 2 10
Lenovo Thinkpad 8
Lenovo Thinkpad 10 (gen 1)

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