nfp: refactor policer config to support ingress/egress meter

Add an policer API to support ingress/egress meter.

Change ingress police to compatible with the new API.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Louis Peens <louis.peens@corigine.com>
Signed-off-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>