powerpc/85xx & 86xx: Rework ft_fsl_pci_setup to not require aliases

Previously we used an alias the pci node to determine which node to
fixup or delete.  Now we use the new fdt_node_offset_by_compat_reg to
find the node to update.

Additionally, we replace the code in each board with a single macro call
that makes assumes uniform naming and reduces duplication in this area.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>