block: Correct a documentation comment in blk-cgroup.c

Commit 99e6038
("blk-cgroup: pass a gendisk to the blkg allocation helpers") changed
blkg_alloc() to take a struct gendisk instead of a struct request_queue,
but the documentation comment still referred to q.

So, update that comment to refer to disk instead and fix a typo.

Signed-off-by: Nicky Chorley <ndchorley@gmail.com>
Link: https://lore.kernel.org/r/20240114191056.6992-1-ndchorley@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: ndchorley

block/blk-cgroup.c

@@ -300,7 +300,7 @@ static inline struct blkcg *blkcg_parent(struct blkcg *blkcg)
  * @disk: gendisk the new blkg is associated with
  * @gfp_mask: allocation mask to use
  *
- * Allocate a new blkg assocating @blkcg and @q.
+ * Allocate a new blkg associating @blkcg and @disk.
  */
 static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct gendisk *disk,
 				   gfp_t gfp_mask)