ASoC: SOF: mediatek: remove unused variables

To prevent confusion on the follow-up platform, it is necessary to
remove any unused variables within the struct mtk_adsp_chip_info.

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/20231103095433.10475-4-trevor.wu@mediatek.com


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