e1000e: 82579 intermittently disabled during S0->Sx

When repeatedly cycling Sx->S0 states with the network cable unplugged,
the 82579 PHY may not initialize as expected and may require a full power
cycle to recover functionality to the device.  Workaround this by testing
access of the PHY registers after resuming; if that returns unexpected
results toggle the LANPHYPC signal to power cycle the PHY.

This is implemented in the new function e1000_resume_workarounds_pchlan()
which calls another new function, e1000_toggle_lanphypc_value_ich8lan(),
which has been created to reduce code duplication (same functionality
required by a previous workaround).  Also, e1000e_disable_gig_wol_ich8lan
is now e1000_suspend_workarounds_ich8lan to better reflect what it does.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/e1000e/netdev.c b/drivers/net/e1000e/netdev.c
index 888bd9c..c4a23c7 100644
--- a/drivers/net/e1000e/netdev.c
+++ b/drivers/net/e1000e/netdev.c
@@ -5278,7 +5278,7 @@
 		}
 
 		if (adapter->flags & FLAG_IS_ICH)
-			e1000e_disable_gig_wol_ich8lan(&adapter->hw);
+			e1000_suspend_workarounds_ich8lan(&adapter->hw);
 
 		/* Allow time for pending master requests to run */
 		e1000e_disable_pcie_master(&adapter->hw);
@@ -5429,6 +5429,9 @@
 			return err;
 	}
 
+	if (hw->mac.type == e1000_pch2lan)
+		e1000_resume_workarounds_pchlan(&adapter->hw);
+
 	e1000e_power_up_phy(adapter);
 
 	/* report the system wakeup cause from S3/S4 */