IB/mlx5: Change debugfs to have per port contents

When there are multiple ports for single IB(RoCE) device, support
debugfs entries to be available for each port.

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