arm64: dts: fsl-lx2160a: add rev2 support

Add rev2 dtsi. Although uboot fixup can change compatible string
fsl,lx2160a-pcie to fsl,ls2088a-pcie since 2019, it is quite confused and
should correctly reflect hardware status. So add fsl-lx2160a-rev2.dtsi to
overwrite pcie's compatible string.

Add PCIe EP nodes.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>