hw/nvme: reimplement zone reset to allow cancellation

hw/nvme: reimplement zone reset to allow cancellation

Prior to this patch, the aios associated with zone reset are submitted
anonymously (no reference saved to the aiocb from the blk_aio call).

Fix this by resetting the zones one after another, saving a reference to
the aiocb for each reset.

Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>