ASoC: rockchip: spdif: Convert to use devm_snd_dmaengine_pcm_register

Use resource managed API then we can remove snd_dmaengine_pcm_unregister()
and snd_soc_unregister_component() calls in .probe error path and .remove.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@kernel.org>