PCI: layerscape: Fix assigning wrong address to LS2088A pcie cfg1 space

This bug is brought by the commit 3d8553f0 (pci: layerscape: add
LS2088A series SoC pcie support), which only updated cfg_res.start
and did not update the .end field. This causes fdt_resource_size()
getting wrong value when calculate the cfg1 space address.

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
[YS: Revise subject and commit message]
Reviewed-by: York Sun <york.sun@nxp.com>