RDMA/mlx5: Use correct size for device resources

On allocation we use the array size and on destruction num_ports, use the
array size of destruction as well, in this context the array corresponds
to the native/actual ports on the NIC so no need to adjust this logic for
representors.

Signed-off-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>