Implement REQ_OP_ZONE_OPEN, REQ_OP_ZONE_CLOSE and REQ_OP_ZONE_FINISH
support to allow explicit control of zone states.

Contains contributions from Matias Bjorling, Hans Holmberg and
Damien Le Moal.
Acked-by: NMike Snitzer <snitzer@redhat.com>
Reviewed-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NAjay Joshi <ajay.joshi@wdc.com>
Signed-off-by: NMatias Bjorling <matias.bjorling@wdc.com>
Signed-off-by: NHans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: NDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>