dmaengine: pl330: pl330_tasklet init power_down by pch->active

To fix issue like this:
dma-pl330 ff6d0000.dma-controller: pl330_update:1733 Unexpected!
dma-pl330 ff6d0000.dma-controller: DMAC halted!

The root cause is DMA clk is closed when DMA interrupt is
in service. This may happen, as follow:

1. When pl330_terminate_all is called, and set pch->active false,
power_down is true, call pm_runtime_put_autosuspend.
2. Then pl330_tasklet is called, if power_down is also true, call
pm_runtime_put_autosuspend again.
3. DMA is opened again, because the autosuspend is asyn, it may close
the DMA clk. If DMA interrupt is coming, it causes the issue.

Change-Id: Ieefa3d39ed2e8923626d2ee0f95652ea7de9ca67
Reviewed-on: https://tp-biosrd-v02/gerrit/81492
Reviewed-by: Jamess Huang(黃以民) <Jamess_Huang@asus.com>
Tested-by: Jamess Huang(黃以民) <Jamess_Huang@asus.com>

Author: Angus_Wang

drivers/dma/pl330.c

@@ -2171,7 +2171,7 @@ static void pl330_tasklet(unsigned long data)
 		spin_lock(&pch->thread->dmac->lock);
 		_stop(pch->thread);
 		spin_unlock(&pch->thread->dmac->lock);
-		power_down = true;
+		power_down = pch->active;
 		pch->active = false;
 	} else {
 		/* Make sure the PL330 Channel thread is active */