block: fix a typo in comment of BLK_MQ_POLL_STATS_BKTS

Update comment typo _consisitent_ to _consistent_ from following commit.
commit 0206319f ("blk-mq: Fix poll_stat for new size-based bucketing.")

Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Minwoo Im <minwoo.im.dev@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

include/linux/blkdev.h

@@ -49,7 +49,7 @@ struct blk_stat_callback;
 #define BLKDEV_MIN_RQ	4
 #define BLKDEV_MAX_RQ	128	/* Default maximum */
 
-/* Must be consisitent with blk_mq_poll_stats_bkt() */
+/* Must be consistent with blk_mq_poll_stats_bkt() */
 #define BLK_MQ_POLL_STATS_BKTS 16
 
 /*