net/mlx5e: Support offload cls_flower with drop action

Parse tc_cls_flower_offload into device specific commands and program
the hardware to classify and act accordingly.

For example, to drop ICMP (ip_proto 1) packets from specific smac, dmac,
src_ip, src_ip, arriving to interface ens9:

 # tc qdisc add dev ens9 ingress

 # tc filter add dev ens9 protocol ip parent ffff: \
     flower ip_proto 1 \
     dst_mac 7c:fe:90:69:81:62 src_mac 7c:fe:90:69:81:56 \
     dst_ip 11.11.11.11 src_ip 11.11.11.12 indev ens9 \
     action drop

Signed-off-by: Amir Vadai <amir@vadai.me>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>