e1000e: Workaround for dropped packets in Gig/100 speeds on 82579

e1000e: Workaround for dropped packets in Gig/100 speeds on 82579

This is a workaround for a HW erratum on 82579 devices.
Erratum is #23 in Intel 6 Series Chipset and Intel C200 Series Chipset
specification Update June 2013.

Problem: 82579 parts experience packet loss in Gig and 100 speeds
when interconnect between PHY and MAC is exiting K1 power saving state.
This was previously believed to only affect 1Gig speed, but has been observed
at 100Mbs also.

Workaround: Disable K1 for 82579 devices at Gig and 100 speeds.

Signed-off-by: Dave Ertman <davidx.m.ertman@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>