ARM: dts: stm32: Add syscfg on stm32mp1

System configuration controller is mainly used to manage
the compensation cell and other IOs and system related
settings.
Signed-off-by: Christophe Roullier <christophe.roullier@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157c.dtsi

@@ -831,6 +831,11 @@ exti: interrupt-controller@5000d000 {
 			reg = <0x5000d000 0x400>;
 		};
 
+		syscfg: syscon@50020000 {
+			compatible = "st,stm32mp157-syscfg", "syscon";
+			reg = <0x50020000 0x400>;
+		};
+
 		lptimer2: timer@50021000 {
 			#address-cells = <1>;
 			#size-cells = <0>;