arm64: dts: qcom: x1e80100-crd: Fix backlight

The backlight does not work correctly with the current display panel
configuration: It works after boot, but once the display gets disabled it
is not possible to get it back on. It turns out that the ATNA45AF01 panel
needs exactly the same non-standard power sequence as implemented by the
panel-samsung-atna33xc20 driver for sc7180-trogdor-homestar.

Switch the panel in the DT to the new compatible and make two more changes
to make it work correctly:

 1. Add the missing GPIO for the panel EL_ON3 line (EDP_BL_EN on CRD and
    enable-gpios in the DT).
 2. Drop the regulator-always-on for the panel regulator. The panel does
    not seem to power off properly if the regulator stays on.

Fixes: d7e03cce04 ("arm64: dts: qcom: x1e80100-crd: Enable more support")
Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Signed-off-by: Stephan Gerhold <stephan.gerhold@linaro.org>
Reviewed-by: Johan Hovold <johan+linaro@kernel.org>
Tested-by: Johan Hovold <johan+linaro@kernel.org>
Link: https://lore.kernel.org/r/20240715-x1e80100-crd-backlight-v2-3-31b7f2f658a3@linaro.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

arch/arm64/boot/dts/qcom/x1e80100-crd.dts

@@ -268,7 +268,6 @@
 		pinctrl-0 = <&edp_reg_en>;
 		pinctrl-names = "default";
 
-		regulator-always-on;
 		regulator-boot-on;
 	};
 
@@ -724,9 +723,13 @@
 
 	aux-bus {
 		panel {
-			compatible = "edp-panel";
+			compatible = "samsung,atna45af01", "samsung,atna33xc20";
+			enable-gpios = <&pmc8380_3_gpios 4 GPIO_ACTIVE_HIGH>;
 			power-supply = <&vreg_edp_3p3>;
 
+			pinctrl-0 = <&edp_bl_en>;
+			pinctrl-names = "default";
+
 			port {
 				edp_panel_in: endpoint {
 					remote-endpoint = <&mdss_dp3_out>;
@@ -791,6 +794,16 @@
 	status = "okay";
 };
 
+&pmc8380_3_gpios {
+	edp_bl_en: edp-bl-en-state {
+		pins = "gpio4";
+		function = "normal";
+		power-source = <1>; /* 1.8V */
+		input-disable;
+		output-enable;
+	};
+};
+
 &qupv3_0 {
 	status = "okay";
 };