Initial Mellanox switch driver

Adds support for the Mellanox MLNX-OS switch OS, as found on the
SN2100 switch in the LNG lab.

This *will* get confused if you change the port configuration and go
from single links to quad links or vice versa...

Change-Id: I6e095f8b433b3804ca22d6e5f275a6e6a39dae0b
1 file changed