ARM: dts: stm32: Describe Vin power supply on stm32mp15xx-dkx board

Add description for Vin power supply and for peripherals that
are supplied by Vin.
Signed-off-by: Pascal Paillet <p.paillet@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp15xx-dkx.dtsi

@@ -80,6 +80,14 @@ sound {
 		dais = <&sai2a_port &sai2b_port &i2s2_port>;
 		status = "okay";
 	};
+
+	vin: vin {
+		compatible = "regulator-fixed";
+		regulator-name = "vin";
+		regulator-min-microvolt = <5000000>;
+		regulator-max-microvolt = <5000000>;
+		regulator-always-on;
+	};
 };
 
 &adc {
@@ -240,9 +248,18 @@ pmic: stpmic@33 {
 
 		regulators {
 			compatible = "st,stpmic1-regulators";
+			buck1-supply = <&vin>;
+			buck2-supply = <&vin>;
+			buck3-supply = <&vin>;
+			buck4-supply = <&vin>;
 			ldo1-supply = <&v3v3>;
+			ldo2-supply = <&vin>;
 			ldo3-supply = <&vdd_ddr>;
+			ldo4-supply = <&vin>;
+			ldo5-supply = <&vin>;
 			ldo6-supply = <&v3v3>;
+			vref_ddr-supply = <&vin>;
+			boost-supply = <&vin>;
 			pwr_sw1-supply = <&bst_out>;
 			pwr_sw2-supply = <&bst_out>;