Introduce offloading of skbedit mark action.

For example, to mark with 0x1234, all TCP (ip_proto 6) packets arriving
to interface ens9:

 # tc qdisc add dev ens9 ingress
 # tc filter add dev ens9 protocol ip parent ffff: \
     flower ip_proto 6 \
     indev ens9 \
     action skbedit mark 0x1234
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>