The value of tAdvCfgBWDGranRate specifies the explicit number of
kilobits-per-second that should be used as the child's rounding step
value.
When the value of tAdvCfgBWDGranRate is set to '0', the system
removes the operational PIR rounding behavior from all child policers
and queues associated with the policy specified by tAdvCfgPolicyName.