arm64: tegra: Enable PCIe slots in P2972-0000 board

Enable PCIe controller nodes to enable respective PCIe slots on
P2972-0000 board. Following is the ownership of slots by different
PCIe controllers.
Controller-0 : M.2 Key-M slot
Controller-1 : On-board Marvell eSATA controller
Controller-3 : M.2 Key-E slot
Signed-off-by: NVidya Sagar <vidyas@nvidia.com>
Signed-off-by: NThierry Reding <treding@nvidia.com>

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

@@ -191,7 +191,7 @@
 						regulator-boot-on;
 					};
 
-					sd3 {
+					vdd_1v8ao: sd3 {
 						regulator-name = "VDD_1V8AO";
 						regulator-min-microvolt = <1800000>;
 						regulator-max-microvolt = <1800000>;

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

@@ -64,6 +64,47 @@
 		};
 	};
 
+	pcie@14100000 {
+		status = "okay";
+
+		vddio-pex-ctl-supply = <&vdd_1v8ao>;
+
+		phys = <&p2u_hsio_0>;
+		phy-names = "p2u-0";
+	};
+
+	pcie@14140000 {
+		status = "okay";
+
+		vddio-pex-ctl-supply = <&vdd_1v8ao>;
+
+		phys = <&p2u_hsio_7>;
+		phy-names = "p2u-0";
+	};
+
+	pcie@14180000 {
+		status = "okay";
+
+		vddio-pex-ctl-supply = <&vdd_1v8ao>;
+
+		phys = <&p2u_hsio_2>, <&p2u_hsio_3>, <&p2u_hsio_4>,
+		       <&p2u_hsio_5>;
+		phy-names = "p2u-0", "p2u-1", "p2u-2", "p2u-3";
+	};
+
+	pcie@141a0000 {
+		status = "disabled";
+
+		vddio-pex-ctl-supply = <&vdd_1v8ao>;
+
+		phys = <&p2u_nvhs_0>, <&p2u_nvhs_1>, <&p2u_nvhs_2>,
+		       <&p2u_nvhs_3>, <&p2u_nvhs_4>, <&p2u_nvhs_5>,
+		       <&p2u_nvhs_6>, <&p2u_nvhs_7>;
+
+		phy-names = "p2u-0", "p2u-1", "p2u-2", "p2u-3", "p2u-4",
+			    "p2u-5", "p2u-6", "p2u-7";
+	};
+
 	fan: fan {
 		compatible = "pwm-fan";
 		pwms = <&pwm4 0 45334>;