qeth: fix rx checksum offload handling

ethtool is used to change some device driver features
such as RX/TX hardware checksum offloading.
The qeth device driver callback function to
turn on/off RX hardware check sum handling never changes
the hardware configuration.
The NETIF_F_RXCSUM bit is cleared when the feature bitset
type netdev_features_t(64bit) is assigned to 32 a bit
variable.

This patch fixes the NETIF_F_RXCSUM handling.
Also there is no need to manipulate the device's features
bit set as this is done by the caller when no error occurs.

Signed-off-by: Thomas Richter <tmricht@linux.vnet.ibm.com>
Signed-off-by: Ursula Braun <ursula.braun@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/s390/net/qeth_l3_main.c

@@ -3198,8 +3198,7 @@ static int qeth_l3_set_features(struct net_device *dev,
 	netdev_features_t features)
 {
 	struct qeth_card *card = dev->ml_priv;
-	u32 changed = dev->features ^ features;
-	int err;
+	netdev_features_t changed = dev->features ^ features;
 
 	if (!(changed & NETIF_F_RXCSUM))
 		return 0;
@@ -3208,11 +3207,7 @@ static int qeth_l3_set_features(struct net_device *dev,
 	    card->state == CARD_STATE_RECOVER)
 		return 0;
 
-	err = qeth_l3_set_rx_csum(card, features & NETIF_F_RXCSUM);
-	if (err)
-		dev->features = features ^ NETIF_F_RXCSUM;
-
-	return err;
+	return qeth_l3_set_rx_csum(card, features & NETIF_F_RXCSUM ? 1 : 0);
 }
 
 static const struct ethtool_ops qeth_l3_ethtool_ops = {