nfp: flower: add qos offload install and remove functionality.

Add install and remove offload functionality for qos offloads. We
first check that a police filter can be implemented by the VF rate
limiting feature in hw, then we install the filter via the qos
infrastructure. Finally we implement the mechanism for removing
these types of filters.

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>