ramips: use DT trigger for 2G WiFi on ASUS RT-AC51U

Like for the RT-AC54U, this uses a DT trigger for WiFi also at the
RT-AC51U. While at it, rename node and label to wifi2g.

Note that the 5g WiFi LED still isn't supported (see PR #3017 for
further details: https://github.com/openwrt/openwrt/pull/3017 )

Tested-by: Davide Fioravanti <pantanastyle@gmail.com>
Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

target/linux/ramips/dts/mt7620a_asus_rt-ac51u.dts

@@ -28,9 +28,10 @@
 			linux,default-trigger = "usbport";
 		};
 
-		wifi {
-			label = "rt-ac51u:blue:wifi";
+		wifi2g {
+			label = "rt-ac51u:blue:wifi2g";
 			gpios = <&gpio3 0 GPIO_ACTIVE_LOW>;
+			linux,default-trigger = "phy1tpt";
 		};
 	};
 };

target/linux/ramips/mt7620/base-files/etc/board.d/01_leds

@@ -47,12 +47,6 @@ asus,rt-n14u)
 	ucidef_set_led_netdev "wan" "wan" "$boardname:blue:wan" eth0.2
 	set_wifi_led "$boardname:blue:air"
 	;;
-asus,rt-ac51u|\
-kingston,mlw221|\
-kingston,mlwg2|\
-sanlinking,d240)
-	set_wifi_led "$boardname:blue:wifi"
-	;;
 bdcom,wap2100-sk)
 	set_wifi_led "$boardname:green:wlan2g"
 	;;
@@ -139,6 +133,11 @@ kimax,u35wf)
 	set_wifi_led "$boardname:blue:wifi"
 	ucidef_set_led_netdev "eth" "ETH" "$boardname:green:eth" "eth0"
 	;;
+kingston,mlw221|\
+kingston,mlwg2|\
+sanlinking,d240)
+	set_wifi_led "$boardname:blue:wifi"
+	;;
 lava,lr-25g001)
 	ucidef_set_led_netdev "wlan2g" "WiFi 2.4GHz" "$boardname:green:wlan2g" "wlan1"
 	ucidef_set_led_netdev "wlan5g" "WiFi 5GHz" "$boardname:green:wlan5g" "wlan0"