[POWERPC] bootwrapper: Support all-in-one PCI nodes in cuboot-pq2.

Consensus was reached to put PCI nodes at the root of the tree (and not
under /soc), but the phandle to a control node was rejected in favor of
simply not worrying about /pci/reg overlapping /soc/ranges.

This updates cuboot-82xx to not look for the phandle.

Signed-off-by: Scott Wood <scottwood@freescale.com>
Acked-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>