ARM: mvebu: add missing UART labels on Armada 38x

The Armada 38x had a label for UART0, but not UART1. This commit fixes
that.
Signed-off-by: NThomas Petazzoni <thomas.petazzoni@free-electrons.com>
Acked-by: NGregory CLEMENT <gregory.clement@free-electrons.com>
Signed-off-by: NGregory CLEMENT <gregory.clement@free-electrons.com>

arch/arm/boot/dts/armada-38x.dtsi

@@ -216,7 +216,7 @@
 				status = "disabled";
 			};
 
-			serial@12100 {
+			uart1: serial@12100 {
 				compatible = "snps,dw-apb-uart";
 				reg = <0x12100 0x100>;
 				reg-shift = <2>;