arm64: dts: freescale: ls2088a: Add DTS support for FSL's LS2088A SoC

This patch adds the device tree support for FSL LS2088A SoC based on
ARMv8 architecture.

Following levels of DTSI/DTS files have been created for the LS2088A
SoC family:

     - fsl-ls2088a.dtsi:
            DTS-Include file for FSL LS2088A SoC.

     - fsl-ls2088a-qds.dts:
            DTS file for FSL LS2088A QDS board.

     - fsl-ls2088a-rdb.dts:
            DTS file for FSL LS2088A RDB board.

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>