ARM: dts: stm32: add PWR regulators support on stm32mp131

This patch adds STM32 PWR regulators DT support on stm32mp131.
This requires TFA to clear RCC_SECCFGR, is disabled by default
and can only be enabled on board DT level.
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/boot/dts/st/stm32mp131.dtsi

@@ -758,6 +758,30 @@ rcc: rcc@50000000 {
 				 <&scmi_clk CK_SCMI_LSI>;
 		};
 
+		pwr_regulators: pwr@50001000 {
+			compatible = "st,stm32mp1,pwr-reg";
+			reg = <0x50001000 0x10>;
+			status = "disabled";
+
+			reg11: reg11 {
+				regulator-name = "reg11";
+				regulator-min-microvolt = <1100000>;
+				regulator-max-microvolt = <1100000>;
+			};
+
+			reg18: reg18 {
+				regulator-name = "reg18";
+				regulator-min-microvolt = <1800000>;
+				regulator-max-microvolt = <1800000>;
+			};
+
+			usb33: usb33 {
+				regulator-name = "usb33";
+				regulator-min-microvolt = <3300000>;
+				regulator-max-microvolt = <3300000>;
+			};
+		};
+
 		exti: interrupt-controller@5000d000 {
 			compatible = "st,stm32mp13-exti", "syscon";
 			interrupt-controller;