arm64: dts: apple: s800-0-3: Add backlight nodes

Add DWI backlight controller nodes for Apple A9 SoC, and enable it for:

- iPhone 6
- iPhone 6s
- iPhone SE
- iPad 5

Signed-off-by: Nick Chan <towinchenmi@gmail.com>
Link: https://lore.kernel.org/r/20250228-dwi-dt-v2-3-69e450bc4bfb@gmail.com
Signed-off-by: Sven Peter <sven@svenpeter.dev>

arch/arm64/boot/dts/apple/s800-0-3-common.dtsi

@@ -43,6 +43,10 @@
 	};
 };
 
+&dwi_bl {
+	status = "okay";
+};
+
 &serial0 {
 	status = "okay";
 };

arch/arm64/boot/dts/apple/s800-0-3.dtsi

@@ -91,6 +91,13 @@
 			power-domains = <&ps_aic>;
 		};
 
+		dwi_bl: backlight@20e200080 {
+			compatible = "apple,s8000-dwi-bl", "apple,dwi-bl";
+			reg = <0x2 0x0e200080 0x0 0x8>;
+			power-domains = <&ps_dwi>;
+			status = "disabled";
+		};
+
 		pinctrl_ap: pinctrl@20f100000 {
 			compatible = "apple,s8000-pinctrl", "apple,pinctrl";
 			reg = <0x2 0x0f100000 0x0 0x100000>;