realtek: align DT macros in RTL839X with RTL838X

Add a missing definition to the RTL839X DT.

Signed-off-by: Markus Stockhausen <[email protected]>

target/linux/realtek/dts-5.10/rtl839x.dtsi

@@ -29,6 +29,13 @@
 		reg = <##n>; \
 	};
 
+#define EXTERNAL_SFP_PHY_FULL(n, s) \
+	phy##n: ethernet-phy@##n { \
+		compatible = "ethernet-phy-ieee802.3-c22"; \
+		sfp = <&sfp##s>; \
+		reg = <##n>; \
+	};
+
 #define SWITCH_PORT(n, s, m) \
 	port@##n { \
 		reg = <##n>; \