md: remove unneeded semicolon

Eliminate the following coccicheck warning:
./drivers/md/md.c:8208:2-3: Unneeded semicolon
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Yang Li <yang.lee@linux.alibaba.com>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Song Liu <song@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/md/md.c

@@ -8205,7 +8205,7 @@ static void *md_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 			break;
 		mddev = next_mddev;
 		tmp = mddev->all_mddevs.next;
-	};
+	}
 	spin_unlock(&all_mddevs_lock);
 
 	if (to_put)