ASoC: Intel: mfld-pcm: modularize stream allocation code

Tis will be used to add table based support for pcm front ends in subsequent
patches

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

diff --cc sound/soc/intel/sst-mfld-platform-pcm.c
Simple merge

diff --cc sound/soc/intel/sst-mfld-platform.h
Simple merge