net: dsa: sja1105: fix error return code in sja1105_cls_flower_add()

The return value 'rc' maybe overwrite to 0 in the flow_action_for_each
loop, the error code from the offload not support error handling will
not set. This commit fix it to return -EOPNOTSUPP.

Fixes: 6a56e199 ("flow_offload: reject configuration of packet-per-second policing in offload drivers")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>