mmc: block: Check for transfer state in card_busy_detect()

The card is required to return to transfer state. Since that is the state
required to start another transfer, check for that state instead of
programming state.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>