blk: remove bio_set arg from blk_queue_split()

blk: remove bio_set arg from blk_queue_split()

blk_queue_split() is always called with the last arg being q->bio_split,
where 'q' is the first arg.

Also blk_queue_split() sometimes uses the passed-in 'bs' and sometimes uses
q->bio_split.

This is inconsistent and unnecessary.  Remove the last arg and always use
q->bio_split inside blk_queue_split()

Reviewed-by: Christoph Hellwig <[email protected]>
Reviewed-by: Ming Lei <[email protected]>
Credit-to: Javier González <[email protected]> (Noticed that lightnvm was missed)
Reviewed-by: Javier González <[email protected]>
Tested-by: Javier González <[email protected]>
Signed-off-by: NeilBrown <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>