RDMA/core: Avoid copying ifindex twice

rdma_copy_addr copies the ifndex to bound_dev_if.
Therefore avoid copying it again after rdma_copy_addr call is completed.

Signed-off-by: Parav Pandit <parav@mellanox.com>
Reviewed-by: Moni Shoua <monis@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>