igb: No PHPM support in i354 devices

PHY Power Management does not exist for i354 device. So, there is no
need to read and write this register or clear go link Disconnect bit,
which could cause a lot of issues.

Signed-off-by: Akeem G Abodunrin <akeem.g.abodunrin@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>