i2c: mediatek: Add i2c and apdma sync in i2c driver

When i2c and apdma use different source clocks, we should enable
synchronization between them.

Signed-off-by: Qii Wang <qii.wang@mediatek.com>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Matthias Brugger <matthias.bgg@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>