powerpc/85xx: Add binding for CPLD

Some Freescale boards like T1040RDB have an on board CPLD connected on
the IFC bus. Add binding for cpld in board.txt file
Signed-off-by: NPriyanka Jain <Priyanka.Jain@freescale.com>
Signed-off-by: NScott Wood <scottwood@freescale.com>

Documentation/devicetree/bindings/powerpc/fsl/board.txt

@@ -84,3 +84,19 @@ Example:
 		compatible = "fsl,bsc9132qds-fpga", "fsl,fpga-qixis-i2c";
 		reg = <0x66>;
 	};
+
+* Freescale on-board CPLD
+
+Some Freescale boards like T1040RDB have an on board CPLD connected.
+
+Required properties:
+- compatible: Should be a board-specific string like "fsl,<board>-cpld"
+  Example:
+	"fsl,t1040rdb-cpld", "fsl,t1042rdb-cpld", "fsl,t1042rdb_pi-cpld"
+- reg: should describe CPLD registers
+
+Example:
+	cpld@3,0 {
+		compatible = "fsl,t1040rdb-cpld";
+		reg = <3 0 0x300>;
+	};