dmaengine: dw-axi-dmac: use dmaenginem_async_device_register to simplify the code

Use dmaenginem_async_device_register to simplify the code:
	remove dma_async_device_unregister.
Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Signed-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c

@@ -934,7 +934,7 @@ static int dw_probe(struct platform_device *pdev)
 
 	pm_runtime_put(chip->dev);
 
-	ret = dma_async_device_register(&dw->dma);
+	ret = dmaenginem_async_device_register(&dw->dma);
 	if (ret)
 		goto err_pm_disable;
 
@@ -977,8 +977,6 @@ static int dw_remove(struct platform_device *pdev)
 		tasklet_kill(&chan->vc.task);
 	}
 
-	dma_async_device_unregister(&dw->dma);
-
 	return 0;
 }