ramips: provide label MAC for ALFA Network Tube-E4G

Signed-off-by: Piotr Dymacz <[email protected]>

target/linux/ramips/dts/mt7620a_alfa-network_tube-e4g.dts

@@ -11,6 +11,7 @@
 	model = "ALFA Network Tube-E4G";
 
 	aliases {
+		label-mac-device = &ethernet;
 		led-boot = &power;
 		led-failsafe = &power;
 		led-running = &power;