amiflop: use blk_mq_alloc_disk and blk_cleanup_disk

Use blk_mq_alloc_disk and blk_cleanup_disk to simplify the gendisk and
request_queue allocation.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Link: https://lore.kernel.org/r/20210602065345.355274-29-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

drivers/block/amiflop.c

@@ -1781,15 +1781,13 @@ static int fd_alloc_disk(int drive, int system)
 {
 	struct gendisk *disk;
 
-	disk = alloc_disk(1);
-	if (!disk)
-		goto out;
-	disk->queue = blk_mq_init_queue(&unit[drive].tag_set);
-	if (IS_ERR(disk->queue))
-		goto out_put_disk;
+	disk = blk_mq_alloc_disk(&unit[drive].tag_set, NULL);
+	if (IS_ERR(disk))
+		return PTR_ERR(disk);
 
 	disk->major = FLOPPY_MAJOR;
 	disk->first_minor = drive + system;
+	disk->minors = 1;
 	disk->fops = &floppy_fops;
 	disk->events = DISK_EVENT_MEDIA_CHANGE;
 	if (system)
@@ -1802,12 +1800,6 @@ static int fd_alloc_disk(int drive, int system)
 	unit[drive].gendisk[system] = disk;
 	add_disk(disk);
 	return 0;
-
-out_put_disk:
-	disk->queue = NULL;
-	put_disk(disk);
-out:
-	return -ENOMEM;
 }
 
 static int fd_alloc_drive(int drive)