ata: pata_pxa: convert not to use dma_request_slave_channel()

dma_request_slave_channel() is deprecated. dma_request_chan() should
be used directly instead.

Switch to the preferred function and update the error handling accordingly.
While at it, also propagate the error code that is now available.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

drivers/ata/pata_pxa.c

@@ -274,10 +274,9 @@ static int pxa_ata_probe(struct platform_device *pdev)
 	/*
 	 * Request the DMA channel
 	 */
-	data->dma_chan =
-		dma_request_slave_channel(&pdev->dev, "data");
-	if (!data->dma_chan)
-		return -EBUSY;
+	data->dma_chan = dma_request_chan(&pdev->dev, "data");
+	if (IS_ERR(data->dma_chan))
+		return PTR_ERR(data->dma_chan);
 	ret = dmaengine_slave_config(data->dma_chan, &config);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "dma configuration failed: %d\n", ret);