ARM: dts: cygnus: add serial0 alias for uart3 on bcm91130_entphn

Use serial0 alias to select stdout-path on Cygnus bcm911360_entphon
board.
Signed-off-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

arch/arm/boot/dts/bcm911360_entphn.dts

@@ -39,9 +39,12 @@ / {
 	model = "Cygnus Enterprise Phone (BCM911360_ENTPHN)";
 	compatible = "brcm,bcm11360", "brcm,cygnus";
 
+	aliases {
+		serial0 = &uart3;
+	};
+
 	chosen {
-		stdout-path = &uart3;
-		bootargs = "console=ttyS0,115200";
+		stdout-path = "serial0:115200n8";
 	};
 
 	gpio_keys {