mmc: rtsx: add support for sdio card

Modify transfer mode for support sdio card,
send cmd and data at the same time for read data transfer,
but send data after cmd for write data transfer.
Signed-off-by: Micky Ching <micky_ching@realsil.com.cn>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>