arm: mvebu: turris_omnia: Set ETHPRIME to DT alias

CONFIG_ETHPRIME can be set to DT node name or alias which refers to DT
node. Define ethernet aliases and set ETHPRIME to eth2 which refers to WAN
ethernet port. This removes hardcoded DT node name from U-Boot
configuration file.

Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/arch/arm/dts/armada-385-turris-omnia.dts b/arch/arm/dts/armada-385-turris-omnia.dts
index 5511c84..7f1478e 100644
--- a/arch/arm/dts/armada-385-turris-omnia.dts
+++ b/arch/arm/dts/armada-385-turris-omnia.dts
@@ -55,6 +55,12 @@
 		stdout-path = &uart0;
 	};
 
+	aliases {
+		ethernet0 = &eth0;
+		ethernet1 = &eth1;
+		ethernet2 = &eth2;
+	};
+
 	memory {
 		device_type = "memory";
 		reg = <0x00000000 0x40000000>; /* 1024 MB */