Fix warning on 64bit

Because the template instantiation rules of C++ do not deal well with
null pointers specified as '0', the constructor of 'Local_addr' was
instantiated for [T = int], which does not make sense. To avoid the
warning "cast to pointer from integer of different size", we need to
explicitly state that '0' is a pointer. In C++11, there is the 'nullptr'
keyword, but until we switch to this version, we have to state (void *)0.
acpi: Adjust device_pd quota for 64bit machines