soc/intel_adsp: Add SIMCALL output to the trace_out driver

When running under a simulator, it's difficult to extract output from
the window (it's difficult with hardware too!).  Add "SIMCALL" output
to stderr (it's literally just 3 extra instructions) as an optional
feature so this subsystem itself can be debugged without herculean
effort.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>