When the Port Disable bit is set in the Link Default Override Mask TLV PFA
module in the NVM, Total Port Shutdown mode is supported and enabled.  In
this mode, the driver should act as if the link-down-on-close ethtool
private flag is always enabled and dis-allow any change to that flag.
Signed-off-by: NBruce Allan <bruce.w.allan@intel.com>
Signed-off-by: NPaul Greenwalt <paul.greenwalt@intel.com>
Tested-by: NAndrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: NTony Nguyen <anthony.l.nguyen@intel.com>