mmc: dw_mmc: Add a return in an unexpected cmd11 timeout

If we get an unexpected cmd11 timeout we shouldn't actually treat it
as a timeout (not that we really expect to get an unexpected cmd11
timeout, but still).

Fixes: 5c935165 ("mmc: dw_mmc: Add a timeout for sending CMD11")
Reported-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>