crypto: stm32/hash - Use dma_request_chan() instead dma_request_slave_channel()

dma_request_slave_channel() is a wrapper on top of dma_request_chan()
eating up the error code.

By using dma_request_chan() directly the driver can support deferred
probing against DMA.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

drivers/crypto/stm32/stm32-hash.c

@@ -518,10 +518,10 @@ static int stm32_hash_dma_init(struct stm32_hash_dev *hdev)
 	dma_conf.dst_maxburst = hdev->dma_maxburst;
 	dma_conf.device_fc = false;
 
-	hdev->dma_lch = dma_request_slave_channel(hdev->dev, "in");
-	if (!hdev->dma_lch) {
+	hdev->dma_lch = dma_request_chan(hdev->dev, "in");
+	if (IS_ERR(hdev->dma_lch)) {
 		dev_err(hdev->dev, "Couldn't acquire a slave DMA channel.\n");
-		return -EBUSY;
+		return PTR_ERR(hdev->dma_lch);
 	}
 
 	err = dmaengine_slave_config(hdev->dma_lch, &dma_conf);