ARM: dts: stm32: Add RTC support for STM32F746 MCU

This patch adds STM32 RTC bindings for STM32F746.
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Alexandre TORGUE <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32f746.dtsi

@@ -121,6 +121,20 @@ timer7: timer@40001400 {
 			status = "disabled";
 		};
 
+		rtc: rtc@40002800 {
+			compatible = "st,stm32-rtc";
+			reg = <0x40002800 0x400>;
+			clocks = <&rcc 1 CLK_RTC>;
+			clock-names = "ck_rtc";
+			assigned-clocks = <&rcc 1 CLK_RTC>;
+			assigned-clock-parents = <&rcc 1 CLK_LSE>;
+			interrupt-parent = <&exti>;
+			interrupts = <17 1>;
+			interrupt-names = "alarm";
+			st,syscfg = <&pwrcfg>;
+			status = "disabled";
+		};
+
 		usart2: serial@40004400 {
 			compatible = "st,stm32f7-usart", "st,stm32f7-uart";
 			reg = <0x40004400 0x400>;