nfp: flower: check L4 matches on unknown IP protocols

Matching on fields with a protocol that is unknown to hardware
is not strictly unsupported. Determine if hardware can offload
a filter with an unknown protocol by checking if any L4 fields
are being matched as well.

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