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/p2020rdb-pc_36b.dts b/arch/powerpc/dts/p2020rdb-pc_36b.dts
index 542fffc..ecdc022 100644
--- a/arch/powerpc/dts/p2020rdb-pc_36b.dts
+++ b/arch/powerpc/dts/p2020rdb-pc_36b.dts
@@ -41,6 +41,7 @@
 	};
 };
 
+/include/ "p2020rdb-pc.dtsi"
 /include/ "p2020-post.dtsi"
 
 &espi0 {