ASoC: rockchip: vad: optimize vad process

* support vad preprocess
* support buffer-time config
* support channel map
* support data convert

Change-Id: I0728838b3bb2c8a0537560483cab1fb3dd8a4d9c
Signed-off-by: Sugar Zhang <sugar.zhang@rock-chips.com>

Author: Sugar Zhang

Documentation/devicetree/bindings/sound/rockchip,vad.txt

@@ -9,6 +9,7 @@ Required properties:
 - clock-names: should contain following:
 - interrupts: should contain the vad interrupt.
 - rockchip,audio-src: the audio src for vad.
+- rockchip,buffer-time-ms: vad sram buffer time msec.
 - rockchip,det-channel: the channel(0~7) is used for detection.
 - rockchip,mode: vad work mode.
   - 0: begin to store the data after voice detected.

include/sound/pcm.h

@@ -1416,6 +1416,8 @@ snd_pcm_uframes_t snd_pcm_vad_avail(struct snd_pcm_substream *substream);
  * Result is true for attached or false for detached
  */
 bool snd_pcm_vad_attached(struct snd_pcm_substream *substream);
+int snd_pcm_vad_preprocess(struct snd_pcm_substream *substream,
+			   void *buf, snd_pcm_uframes_t size);
 #endif
 
 /* printk helpers */