Having two DMICs, a front DMIC and a Rear DMIC,
but only host audio input AUX port0 is used for these two Dmics.
A "dmic-gpios" property is used for a mixer control to switch
the dmic signal source between the Front and Rear Dmic.
Refer to this one as an example,
commit 3cfbf07c6d27
("ASoC: qcom: sc7180: Modify machine driver for 2mic")
Signed-off-by: Ajye Huang <ajye_huang@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>