commit 143b648d upstream.

This patch fixes MMC not working issue on O2Micro/BayHub Host, which
requires transfer mode register to be cleared when sending no DMA
command.
Signed-off-by: Peter Guo <peter.guo@bayhubtech.com>
Signed-off-by: Adam Lee <adam.lee@canonical.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>