net/sched: cls_flower: add support for matching on ip tos and ttl

Benefit from the support of ip header fields dissection and
allow users to set rules matching on ipv4 tos and ttl or
ipv6 traffic-class and hoplimit.

Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Reviewed-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>