pcm: rate: fix hw_ptr exceed the boundary
pcm: rate: fix hw_ptr exceed the boundary

For long time test case, the hw_ptr will exceed the boundary, then cause
the avail size wrong.

Signed-off-by: Shengjiu Wang <5bd8013dd2cd1a75f84b8ab60f6057aa461774f0@freescale.com>
Signed-off-by: Takashi Iwai <4596b3305151c7ee743192a95d394341e3d3b644@suse.de>

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