soc/intel_adsp: DMA Stability fix for cavstool

There is a hardware bug with stream reset, it won't stop the stream.
I thought it was limited to just the early versions, but it turns out
that 2.5 has it too in some variants.  Which is frustrating, because
the TGL chromebook I have doesn't like the START clear.  But all
systems work with an extra delay between them, so do that.

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