mips: dts: ralink: mt7621: fix external phy on GB-PC2

The address of the external phy on the mdio bus is 5. Update the devicetree
for GB-PC2 accordingly.

Fixes: 5bc14864 ("staging: mt7621-dts: fix GB-PC2 devicetree")
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Sergio Paracuellos <sergio.paracuellos@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/mips/boot/dts/ralink/mt7621-gnubee-gb-pc2.dts

@@ -83,12 +83,12 @@ &pcie {
 
 &gmac1 {
 	status = "okay";
-	phy-handle = <&ethphy7>;
+	phy-handle = <&ethphy5>;
 };
 
 &mdio {
-	ethphy7: ethernet-phy@7 {
-		reg = <7>;
+	ethphy5: ethernet-phy@5 {
+		reg = <5>;
 		phy-mode = "rgmii-rxid";
 	};
 };