arm64: dts: imx8mq-librem5: add vin-supply to VDD_1V8

buck7 is the supply here. Also, fix alphabetical ordering.
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi

@@ -99,6 +99,14 @@ reg_vdd_sen: regulator-vdd-sen {
 		regulator-max-microvolt = <3300000>;
 	};
 
+	reg_vdd_1v8: regulator-vdd-1v8 {
+		compatible = "regulator-fixed";
+		regulator-name = "VDD_1V8";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+		vin-supply = <&buck7_reg>;
+	};
+
 	reg_vdd_3v3: regulator-vdd-3v3 {
 		compatible = "regulator-fixed";
 		regulator-name = "VDD_3V3";
@@ -106,13 +114,6 @@ reg_vdd_3v3: regulator-vdd-3v3 {
 		regulator-max-microvolt = <3300000>;
 	};
 
-	reg_vdd_1v8: regulator-vdd-1v8 {
-		compatible = "regulator-fixed";
-		regulator-name = "VCC_1V8";
-		regulator-min-microvolt = <1800000>;
-		regulator-max-microvolt = <1800000>;
-	};
-
 	reg_vsys_3v4: regulator-vsys-3v4 {
 		compatible = "regulator-fixed";
 		regulator-name = "VSYS_3V4";