Nothing in the core has used it for some time. It's exported to the
plugin API but the last plugins to use it were switched to the mixer API
back in 2011.
This allows us to get rid of pcm_play_dma_pause() from all audio drivers
Change-Id: Ic3fa02592316f84963e41d792d1cabb436d1ff6b
Most credit goes to: Roman Skylarov
Additional integration and refactoring by myself.
*** COMPLETELY UNTESTED ***
Change-Id: Ia64c36d92e0214c6b15f7a868df286f8113ea27b