If an attempt is made to disable RX checksums, USB adapter is changed
but netdev->features is not, because smsc75xx_set_features() returns a
non zero value.
This throws errors from netdev_rx_csum_fault() :
<devname>: hw csum failure
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Steve Glendinning <steve.glendinning@shawell.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
        /* it's racing here! */
 
        ret = smsc75xx_write_reg(dev, RFE_CTL, pdata->rfe_ctl);
-       if (ret < 0)
+       if (ret < 0) {
                netdev_warn(dev->net, "Error writing RFE_CTL\n");
-
-       return ret;
+               return ret;
+       }
+       return 0;
 }
 
 static int smsc75xx_wait_ready(struct usbnet *dev, int in_pm)