Side effects:
 - TX offloads (HW csum, scatter-gather) can be toggled now
 - RX checksum is reported correctly now (it's always active)
Signed-off-by: NMichał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>