e1000e: rework disable K1 at 1000Mbps for 82577/82578

This patch reworks a previous workaround (commit 7d3cabbcc) for an issue
in hardware where noise on the interconnect between the MAC and PHY could
be generated by a lower power mode (K1) at 1000Mbps resulting in bad
packets.  Disable K1 while at 1000 Mbps but keep it enabled for 10/100Mbps
and when the cable is disconnected.  The original version of this
workaround was found to be incomplete.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/e1000e/hw.h b/drivers/net/e1000e/hw.h
index 7b05cf4..aaea41e 100644
--- a/drivers/net/e1000e/hw.h
+++ b/drivers/net/e1000e/hw.h
@@ -903,6 +903,7 @@
 struct e1000_dev_spec_ich8lan {
 	bool kmrn_lock_loss_workaround_enabled;
 	struct e1000_shadow_ram shadow_ram[E1000_ICH8_SHADOW_RAM_WORDS];
+	bool nvm_k1_enabled;
 };
 
 struct e1000_hw {