RDMA/nldev: Provide netdevice name and index

Export the net device name and index to easily find connection
between IB devices and relevant net devices.

We also updated the comment regarding the devices without FW.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Reviewed-by: Steve Wise <swise@opengridcomputing.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>