arm: dts: agilex: Add base dtsi and devkit dts

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>
diff --git a/arch/arm/dts/Makefile b/arch/arm/dts/Makefile
index 0127a91..1ad882f 100644
--- a/arch/arm/dts/Makefile
+++ b/arch/arm/dts/Makefile
@@ -329,6 +329,7 @@
 dtb-$(CONFIG_THUNDERX) += thunderx-88xx.dtb
 
 dtb-$(CONFIG_ARCH_SOCFPGA) +=				\
+	socfpga_agilex_socdk.dtb			\
 	socfpga_arria5_socdk.dtb			\
 	socfpga_arria10_socdk_sdmmc.dtb			\
 	socfpga_cyclone5_mcvevk.dtb			\