armv8: fsl-layerscpae: correct the PCIe controllers' region size

The LS2080A has 8GB region for each PCIe controller, while the
other platforms have 32GB.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Prabhakar Kushwaha <prabhakar.kushwaha@nxp.com>