ARM: dts: exynos: add backlight supply in P4 Note

The LCD backlight  should have a supply.  Use same regulator as LCD, to
silence warning:

  exynos4412-p4note-n8010.dtb: backlight: 'power-supply' is a required property

Link: https://lore.kernel.org/r/20230120155404.323386-8-krzysztof.kozlowski@linaro.orgSigned-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

arch/arm/boot/dts/exynos4412-p4note.dtsi

@@ -245,6 +245,7 @@ backlight: backlight {
 		pinctrl-0 = <&led_bl_reset>;
 		pinctrl-names = "default";
 		enable-gpios = <&gpm0 1 GPIO_ACTIVE_HIGH>;
+		power-supply = <&panel_vdd>;
 		pwms = <&pwm 1 78770 0>;
 		brightness-levels = <0 48 128 255>;
 		num-interpolated-steps = <8>;