ARM: at91/dt: kizbox: use stdout-path

The kizbox dts are using the deprecated linux,stdout-path. Replace those by
stdout-path.
Signed-off-by: NAlexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: NGaël PORTAY <g.portay@overkiz.com>
Signed-off-by: NNicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/boot/dts/at91-kizbox.dts

@@ -16,7 +16,7 @@
 
 	chosen {
 		bootargs = "ubi.mtd=ubi";
-		linux,stdout-path = &dbgu;
+		stdout-path = &dbgu;
 	};
 
 	memory {

arch/arm/boot/dts/at91-kizbox2.dts

@@ -15,7 +15,7 @@
 
 	chosen {
 		bootargs = "ubi.mtd=ubi";
-		linux,stdout-path = &dbgu;
+		stdout-path = &dbgu;
 	};
 
 	memory {

arch/arm/boot/dts/at91-kizboxmini.dts

@@ -15,7 +15,7 @@
 
 	chosen {
 		bootargs = "ubi.mtd=ubi";
-		linux,stdout-path = &dbgu;
+		stdout-path = &dbgu;
 	};
 
 	memory {