ASoC: ep93xx: Open code dma channel request

Currently the ep93xx DMA code is one of the few users relying on the fact
that the compat code uses the dma_data as the filter data for non-DT
channel requests. Since the rest of the core expects this to be a struct
snd_dmaengine_dai_data this isn't terribly helpful this will be changed to
use the already existing filter data so avoid breaking ep93xx by open
coding the current behaviour.

Signed-off-by: Mark Brown <broonie@linaro.org>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>

sound/soc/cirrus/ep93xx-pcm.c

@@ -57,9 +57,22 @@ static bool ep93xx_pcm_dma_filter(struct dma_chan *chan, void *filter_param)
 	return false;
 }
 
+static struct dma_chan *ep93xx_compat_request_channel(
+	struct snd_soc_pcm_runtime *rtd,
+	struct snd_pcm_substream *substream)
+{
+	struct snd_dmaengine_dai_dma_data *dma_data;
+
+	dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);
+
+	return snd_dmaengine_pcm_request_channel(ep93xx_pcm_dma_filter,
+						 dma_data);
+}
+
 static const struct snd_dmaengine_pcm_config ep93xx_dmaengine_pcm_config = {
 	.pcm_hardware = &ep93xx_pcm_hardware,
 	.compat_filter_fn = ep93xx_pcm_dma_filter,
+	.compat_request_channel = ep93xx_compat_request_channel,
 	.prealloc_buffer_size = 131072,
 };