ASoC: SOF: mediatek: mt8186: clean up unused code

Since there are some variables that are no longer being used, we remove
the code that was implemented for those variables.

Signed-off-by: Trevor Wu <trevor.wu@mediatek.com>
Reviewed-by: Yaochun Hung <yc.hung@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20231103095433.10475-3-trevor.wu@mediatek.com


Signed-off-by: Mark Brown <broonie@kernel.org>