mmc: mediatek: fix controller busy when plug out SD

when plug out SD card, may get data CRC error, the MMC core will issue
CMD13 to get card status, then CMD13 timeout(due to card plug out) will
trigger CMD19 tuning, first CMD19 timeout has not call msdc_reset_hw()
and cause the next CMD19 gets controller busy.

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