mmc: mtk-sd: Add support for MT8196

Mediatek SoC MT8196 features a new design for tx/rx path. The new tx
path incorporates register settings that are closely associated with
bus timing. And the difference between new rx path and older versions
is the usage of distinct register bits when setting the data sampling
edge as part of the tuning process.

Besides, the register settings for STOP_DLY_SEL and POP_EN_CNT are
different from previous SoCs.

For the changes mentioned in relation to the MT8196, the new compatible
string 'mediatek,mt8196-mmc' is introduced. This is to accommodate
different settings and workflows specific to the MT8196.

Signed-off-by: Andy-ld Lu <andy-ld.lu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Message-ID: <20241011024906.8173-3-andy-ld.lu@mediatek.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>