ixgbe: add support for x540 MAC

This patch adds support for the x540 MAC which is the next MAC in the
82598/82599 line.

Signed-off-by: Don Skidmore <donald.c.skidmore@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
diff --git a/drivers/net/ixgbe/ixgbe_dcb.c b/drivers/net/ixgbe/ixgbe_dcb.c
index 4f2f0ae..d16c260 100644
--- a/drivers/net/ixgbe/ixgbe_dcb.c
+++ b/drivers/net/ixgbe/ixgbe_dcb.c
@@ -152,10 +152,17 @@
                         struct ixgbe_dcb_config *dcb_config)
 {
 	s32 ret = 0;
-	if (hw->mac.type == ixgbe_mac_82598EB)
+	switch (hw->mac.type) {
+	case ixgbe_mac_82598EB:
 		ret = ixgbe_dcb_hw_config_82598(hw, dcb_config);
-	else if (hw->mac.type == ixgbe_mac_82599EB)
+		break;
+	case ixgbe_mac_82599EB:
+	case ixgbe_mac_X540:
 		ret = ixgbe_dcb_hw_config_82599(hw, dcb_config);
+		break;
+	default:
+		break;
+	}
 	return ret;
 }