ARM: dts: imx6-phytec: Use the standard 'stdout-path' property

Use the standard 'stdout-path' property to fix the following DTC warnings:

arch/arm/boot/dts/imx6dl-phytec-mira-rdk-nand.dtb: Warning
(chosen_node_stdout_path): /chosen:linux,stdout-path: Use
'stdout-path' instead
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6dl-phytec-mira-rdk-nand.dts

@@ -15,7 +15,7 @@ / {
 		     "phytec,imx6qdl-pcm058", "fsl,imx6dl";
 
 	chosen {
-		linux,stdout-path = &uart2;
+		stdout-path = &uart2;
 	};
 };
 

arch/arm/boot/dts/imx6q-phytec-mira-rdk-emmc.dts

@@ -15,7 +15,7 @@ / {
 		     "phytec,imx6qdl-pcm058", "fsl,imx6q";
 
 	chosen {
-		linux,stdout-path = &uart2;
+		stdout-path = &uart2;
 	};
 };
 

arch/arm/boot/dts/imx6q-phytec-mira-rdk-nand.dts

@@ -15,7 +15,7 @@ / {
 		     "phytec,imx6qdl-pcm058", "fsl,imx6q";
 
 	chosen {
-		linux,stdout-path = &uart2;
+		stdout-path = &uart2;
 	};
 };
 

arch/arm/boot/dts/imx6qp-phytec-mira-rdk-nand.dts

@@ -15,7 +15,7 @@ / {
 		     "phytec,imx6qdl-pcm058", "fsl,imx6qp";
 
 	chosen {
-		linux,stdout-path = &uart2;
+		stdout-path = &uart2;
 	};
 };