drbd: atomically update queue limits in drbd_reconsider_queue_parameters

Switch drbd_reconsider_queue_parameters to set up the queue parameters
in an on-stack queue_limits structure and apply the atomically.  Remove
various helpers that have become so trivial that they can be folded into
drbd_reconsider_queue_parameters.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20240305134041.137006-8-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>