ucm2: codecs: wcd938x: use Analog volume for HeadPhones
Current setup used Digital Volume to control Headset Volume which is
pretty saturated after centain gain. Fix the Digital gain at 0dB and use
Analog gain to do the volume control.
Closes: https://github.com/alsa-project/alsa-ucm-conf/pull/335 Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> Reviewed-by: Johan Hovold <johan+linaro@kernel.org> Tested-by: Johan Hovold <johan+linaro@kernel.org> Signed-off-by: Jaroslav Kysela <perex@perex.cz>