net/mlx4_core: Expose physical port id as PF/VF capability

Add the infrastructure needed to support ndo_get_phys_port_id which
allows users to identify to which physical port a net-device is connected
to by reading a unique port id.
This will work for VFs and PFs.
The driver uses a new device capability - phys_port_id, The PF driver
reads the port phys_port_id from Firmware and stores it. The VF driver
reads the port phys_port_id from the PF using QUERY_FUNC_CAP command.

Signed-off-by: Hadar Hen Zion <hadarh@mellanox.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>