ASoC: soc-generic-dmaengine: Handle DMA channel request failures correctly

ASoC: soc-generic-dmaengine: Handle DMA channel request failures correctly

Currently any dma_request_chan() failure other than -EPROBE_DEFER is
silently ignored, since a missing channel is expected for devices that
only support one DMA direction.

Improve the handling of these failures by:
- reporting failures when a configured DMA channel cannot be requested;
- failing probe if neither playback nor capture obtains a DMA channel,
  since the PCM device would be unusable.

Devices that legitimately support only one DMA direction continue to
work as before.

Signed-off-by: bui duc phuc <phucduc.bui@gmail.com>
Link: https://patch.msgid.link/20260720064131.75156-1-phucduc.bui@gmail.com
Signed-off-by: Mark Brown <broonie@kernel.org>