IB/core: Use valid port number to check link layer

IB HCA port starts from 1. Use IB core provided port iterator API to avoid
any assumption with start port number.

Link: https://lore.kernel.org/r/20210127150010.1876121-11-leon@kernel.org


Signed-off-by: Parav Pandit <parav@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>