mmc: mediatek: support 24bits segment size

MSDC IP which support 64G DRAM will support 24bits BDMA buffer length,
so add support it.

Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
1 file changed