block: correctly report cache type

Check the features flag and the override flag using the
blk_queue_write_cache, helper otherwise we're going to always
report "write through".

Fixes: 1122c0c1 ("block: move cache control settings out of queue->flags")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Link: https://lore.kernel.org/r/20240626142637.300624-3-hch@lst.deSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-sysfs.c

@@ -453,9 +453,9 @@ static ssize_t queue_io_timeout_store(struct request_queue *q, const char *page,
 
 static ssize_t queue_wc_show(struct request_queue *q, char *page)
 {
-	if (q->limits.features & BLK_FLAG_WRITE_CACHE_DISABLED)
-		return sprintf(page, "write through\n");
-	return sprintf(page, "write back\n");
+	if (blk_queue_write_cache(q))
+		return sprintf(page, "write back\n");
+	return sprintf(page, "write through\n");
 }
 
 static ssize_t queue_wc_store(struct request_queue *q, const char *page,