arm64: tegra: Add PCIe slot supply information in p2972-0000 platform

Add 3.3V and 12V supplies regulators information of x16 PCIe slot in
p2972-0000 platform which is owned by C5 controller and also enable C5
controller.
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Andrew Murray <andrew.murray@arm.com>

arch/arm64/boot/dts/nvidia/tegra194-p2888.dtsi

@@ -289,5 +289,29 @@ vdd_hdmi: regulator@1 {
 			gpio = <&gpio TEGRA194_MAIN_GPIO(A, 3) GPIO_ACTIVE_HIGH>;
 			enable-active-high;
 		};
+
+		vdd_3v3_pcie: regulator@2 {
+			compatible = "regulator-fixed";
+			reg = <2>;
+
+			regulator-name = "PEX_3V3";
+			regulator-min-microvolt = <3300000>;
+			regulator-max-microvolt = <3300000>;
+			gpio = <&gpio TEGRA194_MAIN_GPIO(Z, 2) GPIO_ACTIVE_HIGH>;
+			regulator-boot-on;
+			enable-active-high;
+		};
+
+		vdd_12v_pcie: regulator@3 {
+			compatible = "regulator-fixed";
+			reg = <3>;
+
+			regulator-name = "VDD_12V";
+			regulator-min-microvolt = <1200000>;
+			regulator-max-microvolt = <1200000>;
+			gpio = <&gpio TEGRA194_MAIN_GPIO(A, 1) GPIO_ACTIVE_LOW>;
+			regulator-boot-on;
+			enable-active-low;
+		};
 	};
 };

arch/arm64/boot/dts/nvidia/tegra194-p2972-0000.dts

@@ -93,9 +93,11 @@ pcie@14180000 {
 	};
 
 	pcie@141a0000 {
-		status = "disabled";
+		status = "okay";
 
 		vddio-pex-ctl-supply = <&vdd_1v8ao>;
+		vpcie3v3-supply = <&vdd_3v3_pcie>;
+		vpcie12v-supply = <&vdd_12v_pcie>;
 
 		phys = <&p2u_nvhs_0>, <&p2u_nvhs_1>, <&p2u_nvhs_2>,
 		       <&p2u_nvhs_3>, <&p2u_nvhs_4>, <&p2u_nvhs_5>,