arm: mvebu: Add DB-XC3-24G4XG board

The DB-XC3-24G4XG is a switch development board from Marvell. It can
either use and external CPU card such as the db-88f6820-amc or the
internal CPU that is integrated into the switch.

Add support for running U-Boot on the internal CPU and enable the USB,
SPI and NAND peripherals. For now this needs the bin_hdr from the
Marvell U-Boot for this board.

Signed-off-by: Chris Packham <judge.packham@gmail.com>
Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/dts/armada-xp-98dx4251.dtsi b/arch/arm/dts/armada-xp-98dx4251.dtsi
new file mode 100644
index 0000000..48ffdc7
--- /dev/null
+++ b/arch/arm/dts/armada-xp-98dx4251.dtsi
@@ -0,0 +1,54 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Device Tree Include file for Marvell 98dx4521 family SoC
+ *
+ * Copyright (C) 2016 Allied Telesis Labs
+ *
+ * Contains definitions specific to the 98dx4521 SoC that are not
+ * common to all Armada XP SoCs.
+ */
+
+#include "armada-xp-98dx3236.dtsi"
+
+/ {
+	model = "Marvell 98DX4251 SoC";
+	compatible = "marvell,armadaxp-98dx4251", "marvell,armadaxp-98dx3236", "marvell,armada-370-xp";
+
+	cpus {
+		cpu@1 {
+			device_type = "cpu";
+			compatible = "marvell,sheeva-v7";
+			reg = <1>;
+			clocks = <&cpuclk 1>;
+			clock-latency = <1000000>;
+		};
+	};
+
+	soc {
+		internal-regs {
+			resume@20980 {
+				compatible = "marvell,98dx3336-resume-ctrl";
+				reg = <0x20980 0x10>;
+			};
+		};
+	};
+};
+
+&sdio {
+	status = "okay";
+};
+
+&pinctrl {
+	compatible = "marvell,98dx4251-pinctrl";
+
+	sdio_pins: sdio-pins {
+		marvell,pins = "mpp5", "mpp6", "mpp7",
+			       "mpp8", "mpp9", "mpp10";
+		marvell,function = "sd0";
+	};
+};
+
+&pp0 {
+	compatible = "marvell,prestera-98dx4251", "marvell,prestera";
+	interrupts = <33>, <34>, <35>, <36>;
+};