hw/nvme: reimplement format nvm to allow cancellation

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

Fix this by formatting the namespaces one after another, saving a
reference to the aiocb for each.

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