arm64: dts: freescale: ls2080a: Split devicetree for code resuability

LS2088A and LS2080A are similar SoCs with a few differences like
ARM cores etc.

Reorganize the LS2080A device tree to move the common nodes to:
        - fsl-ls208xa.dtsi
        - fsl-ls208xa-rdb.dtsi
        - fsl-ls208xa-qds.dtsi

Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>
Signed-off-by: Ashish Kumar <ashish.kumar@nxp.com>
Signed-off-by: Abhimanyu Saini <abhimanyu.saini@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>