intel_adsp: debug_window: Add slot type for debug-stream transport

Add slot type for debug-stream transport over a debug window slot. For
details see src/debug/debug_stream/debug_stream_slot.h under SOF
sources [1].

[1] https://github.com/thesofproject/sof



Signed-off-by: Jyri Sarha <jyri.sarha@linux.intel.com>