mediatek: mt7622: unifi6lr: properly register Ethernet PHY

This change enables proper Ethernet link status and speed reporting on
the Ubiquiti UniFi 6 LR access point:

 mtk_soc_eth 1b100000.ethernet eth0: PHY [mdio-bus:08] driver [Aquantia AQR112C] (irq=POLL)
 mtk_soc_eth 1b100000.ethernet eth0: configuring for phy/2500base-x link mode
 mtk_soc_eth 1b100000.ethernet eth0: Link is Up - 1Gbps/Full - flow control rx/tx

Signed-off-by: Daniel Golle <[email protected]>

target/linux/mediatek/dts/mt7622-ubnt-unifi-6-lr.dtsi

@@ -161,21 +161,17 @@
 		reg = <0>;
 
 		phy-mode = "2500base-x";
-
-		fixed-link {
-			speed = <2500>;
-			full-duplex;
-		};
+		phy-handle = <&phy0>;
+		phy-connection-type = "2500base-x";
 	};
 
 	mdio: mdio-bus {
 		#address-cells = <1>;
 		#size-cells = <0>;
 
-		ethernet-phy@7 {
-			/* Marvell AQRate AQR112W - no driver */
+		phy0: ethernet-phy@8 {
 			compatible = "ethernet-phy-ieee802.3-c45";
-			reg = <0x7>;
+			reg = <0x8>;
 		};
 	};
 };