nvme: consolidate chunk_sectors settings

Move the quirked chunk_sectors setting to the same location as noiob so
one place registers this setting. And since the noiob value is only used
locally, remove the member from struct nvme_ns.

Signed-off-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>