[Edgecore] Add as4500-52p DTS

CPU: Marvell 98DX3530 with integrated CPU
MAC: Marvell 98DX3530
PHY: Marvell 88E1780 x 4 (1G port 16~32)
Marvell 88E2780 x 2 (Migi-G port 33-48)
DRAM: 8GB(MAC) DDR4 SDRAM
AirFlow: Front To Back
Function port: 1 x USB port
1 x RJ45 Mgmt port
1 x RJ45 Console port
Ethernet Port: 48 x 1G
Uplink port: 4xSFP+
PoE: Microsemi PD69208M x 12 + PD69210 x 2

The DTS is for the PR:
dentproject/dentOS#285

Signed-off-by: Brandon Chuang <brandon_chuang@edge-core.com>

Author: brandonchuang

arch/arm64/boot/dts/marvell/accton-as4500-52p.dts

@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: (GPL-2.0+ OR MIT)
+/*
+ * Device Tree For Accton as4500-52p.
+ *
+ * Copyright (C) 2021 Marvell
+ *
+ */
+
+#include "accton-as4500-52p.dtsi"
+
+/ {
+	model = "Marvell AC5X RD board";
+};
+
+&mdio {
+	status = "disabled";
+	pinctrl-names = "default";
+	phy0: ethernet-phy@0 {
+		reg = <0x0>;
+	};
+};
+
+&eth0 {
+	status = "disabled";
+	phy-mode = "sgmii";
+	phy = <&phy0>;
+};
+
+&usb0 {
+	status= "okay";
+};
+
+&usb1 {
+	compatible = "chipidea,usb2";
+	phys = <&usb1phy>;
+	phy-names = "usb-phy";
+	dr_mode = "host";
+};
+