There are two unrelated problems in acpiphp that are fixed by this patch.
First, acpiphp can be a module, so it is unsafe to probe the BARs of each
device while it initialises -- the device may be active at the time.
Second, it does not know about PCI-PCI bridge registers and so it reads
garbage for the last 4 registers of the PCI-PCI bridge card and doesn't
take into account the ranges that are forwarded by the bridge.

This patch avoids all that by using the struct resources embedded in
the pci_dev.  Note that we no longer need to recurse as all the devices
on the other side of a PCI-PCI bridge have their resources entirely
contained within the PCI-PCI bridge's ranges.