pch_gbe: fix if condition in set_settings()

There were no curly braces in this if condition so it always enabled full
duplex.

And ecmd->speed is an unsigned short so it is never equal to -1.  The
effect is that mii_ethtool_sset() fails with -EINVAL and an error is
printed to dmesg.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/pch_gbe/pch_gbe_ethtool.c

@@ -113,9 +113,10 @@ static int pch_gbe_set_settings(struct net_device *netdev,
 
 	pch_gbe_hal_write_phy_reg(hw, MII_BMCR, BMCR_RESET);
 
-	if (ecmd->speed == -1)
+	if (ecmd->speed == USHRT_MAX) {
 		ecmd->speed = SPEED_1000;
 		ecmd->duplex = DUPLEX_FULL;
+	}
 	ret = mii_ethtool_sset(&adapter->mii, ecmd);
 	if (ret) {
 		pr_err("Error: mii_ethtool_sset\n");