ASoC: dmaengine: Extend use of chan_names provided in custom DMA config

There are currently two ways to specify custom DMA channel names:
 - through the SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME flag and
   snd_dmaengine_dai_dma_data data structure,
 - through chan_names field of struct snd_dmaengine_pcm_config.

In order to replace the DAI DMA data method with the custom DMA config
one on non-DT platforms the dmaengine_pcm_new() function is extended
to also consider channel names specified in the custom DMA config.
If both config->chan_names and dma_data->chan_name are provided
the former will be used.
Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Mark Brown <broonie@kernel.org>

sound/soc/soc-generic-dmaengine-pcm.c

@@ -288,9 +288,16 @@ static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
 		dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
 
 		if (!pcm->chan[i] &&
-		    (pcm->flags & SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME))
+		    ((pcm->flags & SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME) ||
+		     (config && config->chan_names[i]))) {
+			const char *chan_name = dma_data->chan_name;
+
+			if (config && config->chan_names[i])
+				chan_name = config->chan_names[i];
+
 			pcm->chan[i] = dma_request_slave_channel(dev,
-				dma_data->chan_name);
+				chan_name);
+		}
 
 		if (!pcm->chan[i] && (pcm->flags & SND_DMAENGINE_PCM_FLAG_COMPAT)) {
 			pcm->chan[i] = dmaengine_pcm_compat_request_channel(rtd,