block, bfq: merge bfq_release_process_ref() into bfq_put_cooperator()

Because bfq_put_cooperator() is always followed by
bfq_release_process_ref().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240909134154.954924-4-yukuai1@huaweicloud.com


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