ASoC: qcom: sc7180: Modify machine driver for 2mic

ASoC: qcom: sc7180: Modify machine driver for 2mic

In addition, having mixer control to switch between DMICs by
using "dmic-gpios" property.

Refer to this one as an example,
commit fbf631d3f80f ("ASoC: AMD: Use mixer control to switch between DMICs")

Signed-off-by: Ajye Huang <ajye_huang@compal.corp-partner.google.com>
Reviewed-by: Tzung-Bi Shih <tzungbi@google.com>
Link: https://lore.kernel.org/r/20201106061433.1483129-3-ajye_huang@compal.corp-partner.google.com
Signed-off-by: Mark Brown <broonie@kernel.org>