nfp: flower: implement ip fragmentation match offload

Implement ip fragmentation match offloading for both IPv4 and IPv6. Allows
offloading frag, nofrag, first and nofirstfrag classification.

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>