nfp: add IPv4 ttl and tos match offloading support

Previously matching on IPv4 ttl and tos fields were not offloaded. This
patch enables offloading IPv4 ttl and tos as match fields.

Signed-off-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>