ARM: dts: stm32: add booster for ADC analog switches on stm32mp157c

Booster for ADC analog input switches can be used when Vdda is below 2.7V
to get maximum ADC analog performances.
Add booster for ADC analog switches on stm32mp157c.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157c.dtsi

@@ -109,6 +109,12 @@ cooling-maps {
 		};
 	};
 
+	booster: regulator-booster {
+		compatible = "st,stm32mp1-booster";
+		st,syscfg = <&syscfg>;
+		status = "disabled";
+	};
+
 	soc {
 		compatible = "simple-bus";
 		#address-cells = <1>;