Fix delayed start with rate plugin
Fix delayed start with rate plugin

Add the internal start_pending state in the rate plugin for supporting
delayed start in the case no data is committed to slave PCM.

This fixes the problem of CPU hog with artsd.

zedongchen/alsa-lib,zedongchen/alsa-lib,mengdonglin/alsa-lib,alsa-project/alsa-lib,zedongchen/alsa-lib,mikelima/alsa-lib,Distrotech/alsa-lib,mengdonglin/alsa-lib,mengdonglin/alsa-lib,mikelima/alsa-lib,takaswie/alsa-lib,lgirdwood/alsa-lib,tiwai/alsa-lib,lgirdwood/alsa-lib,mikelima/alsa-lib,gittup/alsa-lib,mikelima/alsa-lib,zedongchen/alsa-lib,lgirdwood/alsa-lib,tiwai/alsa-lib,tiwai/alsa-lib,Distrotech/alsa-lib,alsa-project/alsa-lib,mengdonglin/alsa-lib,takaswie/alsa-lib,Distrotech/alsa-lib,takaswie/alsa-lib,lgirdwood/alsa-lib,zedongchen/alsa-lib,gittup/alsa-lib,gittup/alsa-lib,gittup/alsa-lib,Distrotech/alsa-lib,Distrotech/alsa-lib,mengdonglin/alsa-lib,alsa-project/alsa-lib,mikelima/alsa-lib,takaswie/alsa-lib,tiwai/alsa-lib,alsa-project/alsa-lib,lgirdwood/alsa-lib,takaswie/alsa-lib