dmaengine: Replace dma_request_slave_channel() by dma_request_chan()

Replace dma_request_slave_channel() by dma_request_chan() as suggested
since the former is deprecated.

Signed-off-by: Andy Shevchenko <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Vinod Koul <[e-mail]>

drivers/dma/imx-sdma.c

···
 	 * dmatest, thus create 'struct imx_dma_data mem_data' for this case.
 	 * Please note in any other slave case, you have to setup chan->private
 	 * with 'struct imx_dma_data' in your own filter function if you want to
-	 * request dma channel by dma_request_channel() rather than
-	 * dma_request_slave_channel(). Othwise, 'MEMCPY in case?' will appear
-	 * to warn you to correct your filter function.
+	 * request DMA channel by dma_request_channel(), otherwise, 'MEMCPY in
+	 * case?' will appear to warn you to correct your filter function.
 	 */
 	if (!data) {
 		dev_dbg(sdmac->sdma->dev, "MEMCPY in case?\n");

include/linux/dmaengine.h

···
 {
 	struct dma_chan *chan;
 
-	chan = dma_request_slave_channel(dev, name);
-	if (chan)
+	chan = dma_request_chan(dev, name);
+	if (!IS_ERR(chan))
 		return chan;
 
 	if (!fn || !fn_param)