ibmphp_find_res_bus
struct bus_node *ibmphp_find_res_bus(u8);
bus = ibmphp_find_res_bus(busno);
bus = ibmphp_find_res_bus(sec_number);
cur_bus = ibmphp_find_res_bus(parent_busno);
bus_cur = ibmphp_find_res_bus(busno);
bus = ibmphp_find_res_bus(sec_number);