nvme: remove nvme_common command cdw10 array

This is a preparation patch which removes the nvme common command cdw10
array and replace with individual fields. This is needed for the nvmet
error log page implementation make is error log page entry offset
assignment easier.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>