memstick: don't call blk_queue_bounce_limit

All in-tree host drivers set up a proper dma mask and use the dma-mapping
helpers.  This means they will be able to deal with any address that we
are throwing at them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>