ACPI: remove comments about debug layer/level to use

I don't think there's any point in cluttering the code with these.
Better to improve the documentation so *anybody* can figure out
what layer & level to use.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>