block: remove THROTL_IOPS_MAX

No one uses THROTL_IOPS_MAX any more, so remove it.

Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220211101149.2368042-2-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>