i2c: mediatek: Add i2c compatible for Mediatek MT8168

Add i2c compatible for MT8168. Compare to MT2712 i2c controller,
MT8168 need to synchronize signal with dma.

Signed-off-by: Kewei Xu <kewei.xu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Qii Wang <qii.wang@mediatek.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>