mmc: sdhci: do not set AUTO_CMD12 for multi-block CMD53

For CMD53 in block mode, the host does not need to stop the transfer,
as it stops when the block count (present in CMD53) is reached.

Signed-off-by: Corneliu Doban <cdoban@broadcom.com>
Signed-off-by: Scott Branden <sbranden@broadcom.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>