devlink: Simplify devlink port API calls

Devlink port already has pointer to the devlink instance and all API
calls that forward these devlink ports to the drivers perform same
"devlink_port->devlink" assignment before actual call.

This patch removes useless parameter and allows us in the future
to create specific devlink_port_ops to manage user space access with
reliable ops assignment.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>