Add device tree files for Agilex SoC platform.
socfpga_agilex-u-boot.dtsi and socfpga_agilex_socdk-u-boot.dts contains
Uboot specific DT properties.
socfpga_agilex.dtsi and socfpga_agilex_socdk.dts are from Linux
(kernel/git/dinguyen/linux.git, commit 6f0bf971bacacc)
Signed-off-by: Ley Foon Tan <ley.foon.tan@intel.com>
Reviewed-by: Simon Goldschmidt <simon.k.r.goldschmidt@gmail.com>
