realtek: switch RTL8231 driver for D-Link DGS-1210

Update the common external GPIO DTSI file for the DGS-1210 devices to
use an MDIO device on the auxilairy MDIO bus, as the original driver was
doing behind the screen.

Switching to the new driver will allow for full pin-control and will no
longer reset pin config set by the bootloader.

Signed-off-by: Sander Vanheule <[email protected]>
(cherry picked from commit 3d6a1a7874c991c4bd9719bf0a92ab6630034c67)

target/linux/realtek/dts/rtl83xx_d-link_dgs-1210_gpio.dtsi

@@ -17,11 +17,22 @@
 			linux,code = <KEY_RESTART>;
 		};
 	};
+};
+
+&mdio_aux {
+	status = "okay";
+
+	gpio1: expander@0 {
+		compatible = "realtek,rtl8231";
+		reg = <0>;
 
-	gpio1: rtl8231-gpio {
-		compatible = "realtek,rtl8231-gpio";
-		#gpio-cells = <2>;
 		gpio-controller;
-		indirect-access-bus-id = <0>;
+		#gpio-cells = <2>;
+		gpio-ranges = <&gpio1 0 0 37>;
+
+		led-controller {
+			compatible = "realtek,rtl8231-leds";
+			status = "disabled";
+		};
 	};
 };