blk-iolatency: don't change the latency window

blk-iolatency: don't change the latency window

Early versions of these patches had us waiting for seconds at a time
during submission, so we had to adjust the timing window we monitored
for latency.  Now we don't do things like that so this is unnecessary
code.

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>