The string defined by user to fill in the
remote ID in the user-defined mode.
If the value of hh3cDhcpSnoop2IfOpt82RIDMode is
NOT 'userDefine', this object is set with a zero-length
string automatically.
Otherwise it must be set with a non-zero length string.
The SET operation of this object must be with the SET
operation of hh3cDhcpSnoop2IfOpt82RIDMode.