realtek: make use of serdes helper for Zyxel XGS1210-12

Use the new INTERNAL_PHY_SDS() helper to describe the SFP ports. For
this device it is only a substitution of the existing DTS configuration.

Signed-off-by: Markus Stockhausen <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/18851
Signed-off-by: Robert Marko <[email protected]>

target/linux/realtek/dts/rtl9302_zyxel_xgs1210-12.dts

@@ -242,22 +242,8 @@
 			// reset-gpios = <&gpio0 21 GPIO_ACTIVE_LOW>;
 		};
 
-		/* SFP0 Ports */
-		phy26: ethernet-phy@26 {
-			compatible = "ethernet-phy-ieee802.3-c22";
-			phy-is-integrated;
-			reg = <26>;
-			sds = < 8 >;
-		};
-
-		/* SFP1 Ports */
-		phy27: ethernet-phy@27 {
-			compatible = "ethernet-phy-ieee802.3-c22";
-			phy-is-integrated;
-			reg = <27>;
-			sds = < 9 >;
-		};
-
+		INTERNAL_PHY_SDS(26, 8)
+		INTERNAL_PHY_SDS(27, 9)
 	};
 };