dts: powerpc: p2020rdb: Add eTSEC DT nodes

P2020RDB implements 3 enhanced three-speed Ethernet controllers,
and the connection is shown below:
    eTSEC1: Connected to RGMII switch VSC7385
    eTSEC2: Connected to SGMII PHY VSC8221
    eTSEC3: Connected to SGMII PHY AR8021

Signed-off-by: Hou Zhiqiang <Zhiqiang.Hou@nxp.com>
[Rebased]
Signed-off-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/arch/powerpc/dts/pq3-etsec1-3.dtsi b/arch/powerpc/dts/pq3-etsec1-3.dtsi
new file mode 100644
index 0000000..853a273
--- /dev/null
+++ b/arch/powerpc/dts/pq3-etsec1-3.dtsi
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0+ OR X11
+/*
+ * PQ3 eTSEC device tree stub [ @ offsets 0x27000 ]
+ *
+ * Copyright 2011-2012 Freescale Semiconductor Inc.
+ * Copyright 2020 NXP
+ */
+
+ethernet@27000 {
+	#address-cells = <1>;
+	#size-cells = <1>;
+	cell-index = <3>;
+	device_type = "network";
+	model = "eTSEC";
+	compatible = "gianfar";
+	reg = <0x27000 0x1000>;
+	ranges = <0x0 0x27000 0x1000>;
+	fsl,magic-packet;
+	local-mac-address = [ 00 00 00 00 00 00 ];
+	interrupts = <37 2 0 0 38 2 0 0 39 2 0 0>;
+};
+
+mdio@27520 {
+	#address-cells = <1>;
+	#size-cells = <0>;
+	compatible = "fsl,gianfar-tbi";
+	reg = <0x27520 0x20>;
+};