Revert "blk-throttle: Fix IO hang for a corner case"

This reverts commit 5b7048b8.

The main purpose of this patch is cleanup.
The throtl_adjusted_limit function was removed after
commit bf20ab53 ("blk-throttle: remove
CONFIG_BLK_DEV_THROTTLING_LOW"), so the problem of not being
able to scale after setting bps or iops to 1 will not occur.
So revert this commit that bps/iops can be set to 1.

Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Signed-off-by: Xiuhong Wang <xiuhong.wang@unisoc.com>
Signed-off-by: Zhiguo Niu <zhiguo.niu@unisoc.com>
Acked-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20241016024508.3340330-1-xiuhong.wang@unisoc.com


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