The value of tSapEgressHsmdaLowBrstMaxCls specifies which class should
use the low priority burst threshold.
All classes starting from 1, up to and including that specified by
tSapEgressHsmdaLowBrstMaxCls use the low priority burst threshold.
All classes greater than the value of tSapEgressHsmdaLowBrstMaxCls up
to and including class 8 use the high priority burst threshold.