mmc: block: Fix incorrectly initialized requests

mmc_init_request() depends on card->bouncesz so it must be calculated
before blk_init_allocated_queue() starts allocating requests.

Reported-by: Seraphime Kirkovski <kirkseraph@gmail.com>
Fixes: 304419d8 ("mmc: core: Allocate per-request data using the..")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Seraphime Kirkovski <kirkseraph@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Pavel Machek <pavel@ucw.cz>