lightnvm: create cmd before allocating request

lightnvm: create cmd before allocating request

Create nvme command before allocating a request using
nvme_alloc_request, which uses the command direction. Up until now, the
command has been zeroized, so all commands have been allocated as a
read operation.

Signed-off-by: Javier González <[email protected]>
Reviewed-by: Matias Bjørling <[email protected]>
Reviewed-by: Christoph Hellwig <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>