ramips: mt7621: fix 5GHz WiFi LED on ZBT WG3526

This fixes the 5GHz WiFi LED which was previously not working.

Signed-off-by: Andreas Ziegler <dev@andreas-ziegler.de>

target/linux/ramips/dts/ZBT-WG3526.dtsi

@@ -111,6 +111,10 @@
 		reg = <0x0000 0 0 0 0>;
 		mediatek,mtd-eeprom = <&factory 0x8000>;
 		ieee80211-freq-limit = <5000000 6000000>;
+
+		led {
+			led-sources = <2>;
+		};
 	};
 };