flow_offload: reject configuration of packet-per-second policing in offload drivers

A follow-up patch will allow users to configures packet-per-second policing
in the software datapath. In preparation for this, teach all drivers that
support offload of the policer action to reject such configuration as
currently none of them support it.

Signed-off-by: Baowen Zheng <baowen.zheng@corigine.com>
Signed-off-by: Simon Horman <simon.horman@netronome.com>
Signed-off-by: Louis Peens <louis.peens@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>