_opp_compare_key
scaling_down = _opp_compare_key(opp_table, old_opp, opp);
opp_cmp = _opp_compare_key(opp_table, new_opp, opp);
if (_opp_compare_key(opp_table, new_opp, opp_table->suspend_opp) == 1) {
int _opp_compare_key(struct opp_table *opp_table, struct dev_pm_opp *opp1, struct dev_pm_opp *opp2);