igb: fix i350 anti spoofing config

Fix a problem in i350 where anti spoofing configuration was written into a
wrong register.

Signed-off-by: Lior Levy <lior.levy@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 b64542a..12b1d84 100644
--- a/drivers/net/ethernet/intel/igb/e1000_82575.c
+++ b/drivers/net/ethernet/intel/igb/e1000_82575.c
@@ -1818,27 +1818,32 @@
  **/
 void igb_vmdq_set_anti_spoofing_pf(struct e1000_hw *hw, bool enable, int pf)
 {
-	u32 dtxswc;
+	u32 reg_val, reg_offset;
 
 	switch (hw->mac.type) {
 	case e1000_82576:
+		reg_offset = E1000_DTXSWC;
+		break;
 	case e1000_i350:
-		dtxswc = rd32(E1000_DTXSWC);
-		if (enable) {
-			dtxswc |= (E1000_DTXSWC_MAC_SPOOF_MASK |
-				   E1000_DTXSWC_VLAN_SPOOF_MASK);
-			/* The PF can spoof - it has to in order to
-			 * support emulation mode NICs */
-			dtxswc ^= (1 << pf | 1 << (pf + MAX_NUM_VFS));
-		} else {
-			dtxswc &= ~(E1000_DTXSWC_MAC_SPOOF_MASK |
-				    E1000_DTXSWC_VLAN_SPOOF_MASK);
-		}
-		wr32(E1000_DTXSWC, dtxswc);
+		reg_offset = E1000_TXSWC;
 		break;
 	default:
-		break;
+		return;
 	}
+
+	reg_val = rd32(reg_offset);
+	if (enable) {
+		reg_val |= (E1000_DTXSWC_MAC_SPOOF_MASK |
+			     E1000_DTXSWC_VLAN_SPOOF_MASK);
+		/* The PF can spoof - it has to in order to
+		 * support emulation mode NICs
+		 */
+		reg_val ^= (1 << pf | 1 << (pf + MAX_NUM_VFS));
+	} else {
+		reg_val &= ~(E1000_DTXSWC_MAC_SPOOF_MASK |
+			     E1000_DTXSWC_VLAN_SPOOF_MASK);
+	}
+	wr32(reg_offset, reg_val);
 }
 
 /**