mmc: mediatek: add DMA mode support

mmc: mediatek: add DMA mode support

Implement DMA support in the MediaTek MMC driver to enhance data
transfer speed.

- Define DMA control and configuration registers
- Implement functions for starting, stopping, and completing DMA
  transfers
- Modify data transfer logic to utilize DMA when enabled
- Ensure proper cache management during DMA operations

Signed-off-by: Wenbin Mei <wenbin.mei@mediatek.com>
Signed-off-by: ht.lin <ht.lin@mediatek.com>
Signed-off-by: Julien Masson <jmasson@baylibre.com>
Signed-off-by: Macpaul Lin <macpaul.lin@mediatek.com>
Signed-off-by: David Lechner <dlechner@baylibre.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>