arm: dts: fsl-ls1088a: sync PCIe controller definition with Linux

arm: dts: fsl-ls1088a: sync PCIe controller definition with Linux

This moves the PCIe controller definitions under /soc and adopts
the same bindings (fsl,ls1088a-pcie) as Linux. Previously,
the format was different between the two versions.

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