alx: treat flow control correctly in alx_set_pauseparam()

Even when alx_setup_speed_duplex() is called, we still
need to call alx_cfg_mac_flowcontrol() and set hw->flowctrl
if flow control changed.

This was a bug I accidentally introduced while simplifying
the original driver.

Reported-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ethernet/atheros/alx/ethtool.c b/drivers/net/ethernet/atheros/alx/ethtool.c
index 6fa2aec..50a91d0 100644
--- a/drivers/net/ethernet/atheros/alx/ethtool.c
+++ b/drivers/net/ethernet/atheros/alx/ethtool.c
@@ -187,7 +187,8 @@
 
 	if (reconfig_phy) {
 		err = alx_setup_speed_duplex(hw, hw->adv_cfg, fc);
-		return err;
+		if (err)
+			return err;
 	}
 
 	/* flow control on mac */