RDMA/core: Refer to network type instead of device type

Set and refer to rdma_dev_addr network type instead of dst->ndev to reduce
dependency on accessing dst netdevice.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Daniel Jurgens <danielj@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>