The value is to remark when yellow action is remarking.
For remark-dscp-continue and remark-dscp-pass, the range is 0~63;
For remark-ip-continue and remark-ip-pass and
remark-mplsexp-continue and remark-mplsexp-pass and
remark-dot1p-continue and remark-dot1p-pass, the range is 0~7;
For remark-fr-de-continue and remark-fr-de-pass and
remark-atm-clp-continue and remark-atm-clp-pass, the range is 0~1.
255 is returned only when getting value from hardware QoS
or when action being pass, discard of software QoS.
255 can't be set.