Add support for inserting and deleting Rx flow classification
rules through ethtool.

We support classification based on some header fields for
flow-types ether, ip4, tcp4, udp4 and sctp4.

Rx queues are core affine, so the action argument effectively
selects on which cpu the matching frame will be processed.
Discarding the frame is also supported.
Signed-off-by: Ioana Radulescu <ruxandra.radulescu@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>