igb: Get speed and duplex for 1G non_copper devices

This patch changes how we get speed/duplex for non_copper devices; it
now uses pcs register to get current speed and duplex instead of using
generic status register that we use to detect speed/duplex for copper
devices.

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>