hw/nvme: consider COPY command in nvme_aio_err

hw/nvme: consider COPY command in nvme_aio_err

If we don't have NVME_CMD_COPY consideration in the switch statement in
nvme_aio_err(), it will go to have NVME_INTERNAL_DEV_ERROR and
`req->status` will be ovewritten to it.  During the aio context, it
might set the NVMe status field like NVME_CMD_SIZE_LIMIT, but it's
overwritten in the nvme_aio_err().

Add consideration for the NVME_CMD_COPY not to overwrite the status at
the end of the function.

Signed-off-by: Minwoo Im <minwoo.im@samsung.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>