mpc8641hpcn: Set up outbound pci windows before inbound

Because the inbound pci windows are mapped generously, set up
the more specific outbound windows first.  This way, when we
search the pci regions for something, we will hit on the more
specific region.  This can actually be a problem on systems
with large amounts of RAM.

Signed-off-by: Becky Bruce <beckyb@kernel.crashing.org>