x86/PCI: VMD: Document code for maintainability

Comment the less obvious portion of the code for setting up memory windows,
and the platform dependency for initializing the h/w with appropriate
resources.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
1 file changed