ASoC: mediatek: mt8188-mt6359: Add DMIC support

ASoC: mediatek: mt8188-mt6359: Add DMIC support

Add the DMIC backend, which connects to the DMIC DAI in the platform
driver, as well as a "AP DMIC" mic widget. On the Genio 700 EVK board
the dual DMIC on-board are wired through that DMIC DAI.

Co-developed-by: parkeryang <Parker.Yang@mediatek.com>
Signed-off-by: parkeryang <Parker.Yang@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Link: https://patch.msgid.link/20250225-genio700-dmic-v2-5-3076f5b50ef7@collabora.com
Signed-off-by: Mark Brown <broonie@kernel.org>