ASoC: samsung: dma: Replace the private pcm operations with the generic ones

ASoC: samsung: dma: Replace the private pcm operations with the generic ones

This patch reshapes the whole samsung platform driver which is composed by
samsung private dmaengine pcm operations, replacing them with the generic
asoc dmaengine pcm operations implemented by alsa soc subsystem.

The dma channel is requested in open callback, and will be released when
the pcm stream is closed. And the pcm trigger operations are also changed
to the asoc generic dmaengine based pcm trigger implementation.

Change-Id: Ib70b973720e5d57a40c7d583b74c11b971b4776c
Signed-off-by: Huang Chao <chao7.huang@samsung.com>