soc/intel_adsp: Increase init priority of trace windows

These windows control host visibility of the trace output buffer.  The
buffer itself is writable memory always, but until we get to the
register init the host can't see them.  Since they contain
printk/logging output, they REALLY need to be initialized earlier than
anything else.

Also remove a rogue memset of the trace buffer.  That buffer is
already being initialized in a lazy-evaluated way by the trace output
code, and blowing it away here has the effect of forgetting anything
earlier code was trying to log!

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