block: fix logging on capacity change

Local variable of 'capacity' stores the previous disk capacity, and
'size' variable records the latest disk capacity, so swap them for
fixing logging on capacity change.

Cc: Christoph Hellwig <hch@lst.de>
Fixes: a782483c ("block: remove the nr_sects field in struct hd_struct")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/genhd.c

@@ -74,7 +74,7 @@ bool set_capacity_and_notify(struct gendisk *disk, sector_t size)
 		return false;
 
 	pr_info("%s: detected capacity change from %lld to %lld\n",
-		disk->disk_name, size, capacity);
+		disk->disk_name, capacity, size);
 
 	/*
 	 * Historically we did not send a uevent for changes to/from an empty