block: Fix queue_iostats_passthrough_show()

Make queue_iostats_passthrough_show() report 0/1 in sysfs instead of 0/4.

This patch fixes the following sparse warning:
block/blk-sysfs.c:266:31: warning: incorrect type in argument 1 (different base types)
block/blk-sysfs.c:266:31:    expected unsigned long var
block/blk-sysfs.c:266:31:    got restricted blk_flags_t

Cc: Keith Busch <kbusch@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>
Fixes: 110234d ("block: enable passthrough command statistics")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20241212212941.1268662-4-bvanassche@acm.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-sysfs.c

@@ -263,7 +263,7 @@ static ssize_t queue_nr_zones_show(struct gendisk *disk, char *page)
 
 static ssize_t queue_iostats_passthrough_show(struct gendisk *disk, char *page)
 {
-	return queue_var_show(blk_queue_passthrough_stat(disk->queue), page);
+	return queue_var_show(!!blk_queue_passthrough_stat(disk->queue), page);
 }
 
 static ssize_t queue_iostats_passthrough_store(struct gendisk *disk,