dts: P1020: Add ESPI DT nodes

Add ESPI controller DT node for P1020.
Signed-off-by: NXiaowei Bao <xiaowei.bao@nxp.com>
Signed-off-by: NHou Zhiqiang <Zhiqiang.Hou@nxp.com>
Reviewed-by: NPriyanka Jain <priyanka.jain@nxp.com>

arch/powerpc/dts/p1020-post.dtsi

@@ -44,6 +44,15 @@
 		clock-frequency = <0>;
 	};
 
+	espi0: spi@7000 {
+		compatible = "fsl,mpc8536-espi";
+		#address-cells = <1>;
+		#size-cells = <0>;
+		reg = <0x7000 0x1000>;
+		fsl,espi-num-chipselects = <4>;
+		status = "disabled";
+	};
+
 	/include/ "pq3-i2c-0.dtsi"
 	/include/ "pq3-i2c-1.dtsi"
 };