arm64: tegra: Add regulators required for PCIe

Add regulator supplies required for PCIe functionality. The supplies
include 1.8V, 3.3V and 12V.
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm64/boot/dts/nvidia/tegra234-p3701-0000.dtsi

@@ -6,6 +6,42 @@ / {
 	model = "NVIDIA Jetson AGX Orin";
 	compatible = "nvidia,p3701-0000", "nvidia,tegra234";
 
+	vdd_1v8_ls: regulator-vdd-1v8-ls {
+		compatible = "regulator-fixed";
+		regulator-name = "VDD_1V8_LS";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+		regulator-always-on;
+	};
+
+	vdd_1v8_ao: regulator-vdd-1v8-ao {
+		compatible = "regulator-fixed";
+		regulator-name = "VDD_1V8_AO";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+		regulator-always-on;
+	};
+
+	vdd_3v3_pcie: regulator-vdd-3v3-pcie {
+		compatible = "regulator-fixed";
+		regulator-name = "VDD_3V3_PCIE";
+		regulator-min-microvolt = <3300000>;
+		regulator-max-microvolt = <3300000>;
+		gpio = <&gpio TEGRA234_MAIN_GPIO(Z, 2) GPIO_ACTIVE_HIGH>;
+		regulator-boot-on;
+		enable-active-high;
+	};
+
+	vdd_12v_pcie: regulator-vdd-12v-pcie {
+		compatible = "regulator-fixed";
+		regulator-name = "VDD_12V_PCIE";
+		regulator-min-microvolt = <12000000>;
+		regulator-max-microvolt = <12000000>;
+		gpio = <&gpio TEGRA234_MAIN_GPIO(A, 1) GPIO_ACTIVE_LOW>;
+		regulator-boot-on;
+		enable-active-low;
+	};
+
 	bus@0 {
 		spi@3270000 {
 			status = "okay";