igb: VFTA Table Fix for i350 devices

Due to a hardware problem, writes to the VFTA register can
theoretically fail. Although the likelihood of this is very low.
This patch adds a shadow vfta in the adapter struct for reading
and adds new write functions for these devices to work around the problem.

Signed-off-by: Carolyn Wyborny <carolyn.wyborny@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/ethernet/intel/igb/e1000_82575.c b/drivers/net/ethernet/intel/igb/e1000_82575.c
index 6580cea..7881fb9 100644
--- a/drivers/net/ethernet/intel/igb/e1000_82575.c
+++ b/drivers/net/ethernet/intel/igb/e1000_82575.c
@@ -1051,7 +1051,10 @@
 
 	/* Disabling VLAN filtering */
 	hw_dbg("Initializing the IEEE VLAN\n");
-	igb_clear_vfta(hw);
+	if (hw->mac.type == e1000_i350)
+		igb_clear_vfta_i350(hw);
+	else
+		igb_clear_vfta(hw);
 
 	/* Setup the receive address */
 	igb_init_rx_addrs(hw, rar_count);