mmc: mediatek: add busy_check support

bit7 of PATCH_BIT1 has different meaning in new design, to
compatible with previous platform, clear this bit in new
platform.

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