block: unexport check_disk_size_change

Only used in block_dev.c and the partitions code, and it should remain
that way..
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

fs/block_dev.c

@@ -1342,7 +1342,6 @@ void check_disk_size_change(struct gendisk *disk, struct block_device *bdev)
 			flush_disk(bdev, false);
 	}
 }
-EXPORT_SYMBOL(check_disk_size_change);
 
 /**
  * revalidate_disk - wrapper for lower-level driver's revalidate_disk call-back