[crojewsk]

This set of patches expose one of the core debug features for DSP:
probes. Probes can be treated as endpoints which allow for data
extraction from or injection to target module. This is paramount when
debugging problematic audio issues such as distortions, glitches or gaps.

Compress streams are a weapon of choice here to provide a lightweight
implementation.

As SOF ipc framework is directly based on /skylake's one, it shares some of its problems. Host can never known upfront size of payload returned by a getter e.g. PROBE_DMA_GET or PROBE_POINT_GET, it can only estimate. Because of this, quick hack has been added to permit PROBE ipcs to work despite non-matching size.

Another point of contention are probe/ compress operations themselves. As these are basically made of hdac_foos and IPCs only, I decided to make this feature Intel specific for now.

_copy function assignment ain't in best place either - due to reason presented above, I've delegated assignment to dbg_init, what again, can be called a hack.