//here we need to set hcdn
//1. hypertransport.c need to record hcdn_reg together with 0xe0, 0xe4, 0xe8, 0xec when are set
//2. so at the same time we need update hsdn with hcdn_reg here
//here we need to set hcdn
//1. hypertransport.c need to record hcdn_reg together with 0xe0, 0xe4, 0xe8, 0xec when are set
//2. so at the same time we need update hsdn with hcdn_reg here