ARM: dts: stm32: add IPCC mailbox support on STM32MP157c

Add configuration on DT for IPCC mailbox driver.
Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157c.dtsi

@@ -886,6 +886,21 @@ usbotg_hs: usb-otg@49000000 {
 			status = "disabled";
 		};
 
+		ipcc: mailbox@4c001000 {
+			compatible = "st,stm32mp1-ipcc";
+			#mbox-cells = <1>;
+			reg = <0x4c001000 0x400>;
+			st,proc-id = <0>;
+			interrupts-extended =
+				<&intc GIC_SPI 100 IRQ_TYPE_LEVEL_HIGH>,
+				<&intc GIC_SPI 101 IRQ_TYPE_LEVEL_HIGH>,
+				<&exti 61 1>;
+			interrupt-names = "rx", "tx", "wakeup";
+			clocks = <&rcc IPCC>;
+			wakeup-source;
+			status = "disabled";
+		};
+
 		rcc: rcc@50000000 {
 			compatible = "st,stm32mp1-rcc", "syscon";
 			reg = <0x50000000 0x1000>;