reboot: Use power off rather than busy spinning when halt is requested

raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

arch/arm/kernel/reboot.c

@@ -102,9 +102,7 @@ void machine_shutdown(void)
  */
 void machine_halt(void)
 {
-	local_irq_disable();
-	smp_send_stop();
-	while (1);
+	machine_power_off();
 }
 
 /*