Create a soc level wrapper for pcm_pointer callback.
This will facilitate the soc level handling of different
HW buffers in the audio path.
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com> Acked-by: Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>