ixgbe: Fix backplane flow control autoneg

Backplane flow control autonegotiation is currently broken for
ixgbe devices.  This patch fixes the flow control issues
with clause 37 autoneg.

Signed-off-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@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/ixgbe/ixgbe_82598.c b/drivers/net/ixgbe/ixgbe_82598.c
index 56b12f3..e2d5343 100644
--- a/drivers/net/ixgbe/ixgbe_82598.c
+++ b/drivers/net/ixgbe/ixgbe_82598.c
@@ -425,7 +425,7 @@
 #endif /* CONFIG_DCB */
 	default:
 		hw_dbg(hw, "Flow control param set incorrectly\n");
-		ret_val = -IXGBE_ERR_CONFIG;
+		ret_val = IXGBE_ERR_CONFIG;
 		goto out;
 		break;
 	}