mmc: remove the call to check_disk_change

The mmc driver doesn't support event notifications, which means
that check_disk_change is a no-op.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/mmc/core/block.c

@@ -312,10 +312,7 @@ static int mmc_blk_open(struct block_device *bdev, fmode_t mode)
 
 	mutex_lock(&block_mutex);
 	if (md) {
-		if (md->usage == 2)
-			check_disk_change(bdev);
 		ret = 0;
-
 		if ((mode & FMODE_WRITE) && md->read_only) {
 			mmc_blk_put(md);
 			ret = -EROFS;