Private rx_csum flags are now duplicate of netdev->features &
NETIF_F_RXCSUM.  Remove those duplicates and use the net_device_ops
ndo_set_features.  This is based on the original patch submitted by
Michał Mirosław <mirq-linux@rere.qmqm.pl>

Cc: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NBruce Allan <bruce.w.allan@intel.com>
Tested-by: NAaron Brown <aaron.f.brown@intel.com>
Signed-off-by: NJeff Kirsher <jeffrey.t.kirsher@intel.com>