powerpc has two different ways of matching PCI devices to their
corresponding OF node (if any) for historical reasons. The ppc64 one
does a scan looking for matching bus/dev/fn, while the ppc32 one does a
scan looking only for matching dev/fn on each level in order to be
agnostic to busses being renumbered (which Linux does on some
platforms).

This removes both and instead moves the matching code to the PCI core
itself. It's the most logical place to do it: when a pci_dev is created,
we know the parent and thus can do a single level scan for the matching
device_node (if any).

The benefit is that all archs now get the matching for free. There's one
hook the arch might want to provide to match a PHB bus to its device
node. A default weak implementation is provided that looks for the
parent device device node, but it's not entirely reliable on powerpc for
various reasons so powerpc provides its own.
Signed-off-by: NBenjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: NMichal Simek <monstr@monstr.eu>
Acked-by: NJesse Barnes <jbarnes@virtuousgeek.org>

There is a tiny difference between PPC32 and PPC64. Microblaze uses the
PPC32 variant.
Signed-off-by: NSebastian Andrzej Siewior <sebastian@breakpoint.cc>
[grant.likely@secretlab.ca: Added comment to #endif, moved documentation
	block to function implementation, fixed for non ppc and microblaze
	compiles]
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>