cal_resume_time: recognize "who cause the delay"

1. main code
    $delay_time_kernel = $PM_request_wake_time - $btn_press_time;
    $delay_time_AP = $display_on_time - $PM_request_wake_time;

    if($delay_time_AP > $delay_time_kernel){
	$who_cause_the_delay = "AP cause";
    } else{
	$who_cause_the_delay = "kernel cause";
    }