armv8: fsl-layerscape: Fix typo in Layerscape PCIe config entry

The correct config entry is CONFIG_PCIE_LAYERSCAPE and this
typo results in skipping the fixup of Linux PCIe DT nodes.

Also enable the fixup when Layerscape Gen4 controller driver
is enabled.

Fixes: 4da0e52c (armv8: fsl-layerscape: fix config dependency
		     for layerscape pci code)

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>