net/sched: cls_flower: Support matching on ARP

Support matching on ARP operation, and hardware and protocol addresses
for Ethernet hardware and IPv4 protocol addresses.

Example usage:

tc qdisc add dev eth0 ingress

tc filter add dev eth0 protocol arp parent ffff: flower indev eth0 \
	arp_op request arp_sip 10.0.0.1 action drop
tc filter add dev eth0 protocol rarp parent ffff: flower indev eth0 \
	arp_op reply arp_tha 52:54:3f:00:00:00/24 action drop

Signed-off-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>