ARM: dts: stm32: enable IPCC mailbox support on STM32MP157a-dk1

Enable STM32 IPCC mailbox driver for STM32MP157a-dk1 board.
Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157a-dk1.dts

@@ -65,6 +65,10 @@ phy0: ethernet-phy@0 {
 	};
 };
 
+&ipcc {
+	status = "okay";
+};
+
 &iwdg2 {
 	timeout-sec = <32>;
 	status = "okay";