pci: layerscape: add support for kernel/official fsl, ls1088a-pcie binding

pci: layerscape: add support for kernel/official fsl, ls1088a-pcie binding

This allows the Layerscape PCIe RC driver to use the upstream
style binding (two "reg" entries instead of four).

It is similar to the previous commit 9ea04411d218
("pci: layerscape: add official ls1028a binding support")
which implemented this for the LS1028A.

Signed-off-by: Mathew McBride <matt@traverse.com.au>
Reviewed-by: Peng Fan <peng.fan@nxp.com>
Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Ioana Ciornei <ioana.ciornei@nxp.com>
Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com> # on LS1088A-RDB