resume changes, please test

I've committed some overall minor changes to the resume assembly code as 
a result of a code review.  Please test to be sure nothing was broken, 
and perhaps something got improved along the way.

Now there is also a tunable/sysctl "debug.acpi.resume_beep".  Setting it 
to 1 will beep the pc speaker very early in resume so we can figure out 
if hangs on resume are a driver or acpi problem.

-- 
Nate