dt-bindings: net: dsa: b53: Fix full duplex in example

There is no such property as duplex-full. It's called full-duplex. Leading to
reduced speed when using the example as base for a real device tree.

Signed-off-by: Kurt Kanzenbach <[e-mail]>
Reviewed-by: Florian Fainelli <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

Documentation/devicetree/bindings/net/dsa/b53.txt

···
 
 		fixed-link {
 			speed = <1000>;
-			duplex-full;
+			full-duplex;
 		};
 	};
 
···
 					label = "cable-modem";
 					fixed-link {
 						speed = <1000>;
-						duplex-full;
+						full-duplex;
 					};
 					phy-mode = "rgmii-txid";
 				};
···
 					label = "cpu";
 					fixed-link {
 						speed = <1000>;
-						duplex-full;
+						full-duplex;
 					};
 					phy-mode = "rgmii-txid";
 					ethernet = <&eth0>;