net: microchip: sparx5: Add support for TC flower ARP dissector

This add support for Sparx5 for dissecting TC ARP flower filter keys and
sets up the Sparx5 IS2 VCAP to generate the ARP keyset for ARP frames.

Signed-off-by: Steen Hegelund <steen.hegelund@microchip.com>
Signed-off-by: David S. Miller <davem@davemloft.net>