ARM: dts: stm32: change default minimal buck1 value on stm32mp157

Minimal value is the value set during boot or before suspend.
We must ensure that the value is a functional value to boot.
Signed-off-by: Pascal Paillet <p.paillet@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

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

@@ -259,7 +259,7 @@ regulators {
 
 			vddcore: buck1 {
 				regulator-name = "vddcore";
-				regulator-min-microvolt = <800000>;
+				regulator-min-microvolt = <1200000>;
 				regulator-max-microvolt = <1350000>;
 				regulator-always-on;
 				regulator-initial-mode = <0>;

arch/arm/boot/dts/stm32mp157c-ed1.dts

@@ -141,7 +141,7 @@ regulators {
 
 			vddcore: buck1 {
 				regulator-name = "vddcore";
-				regulator-min-microvolt = <800000>;
+				regulator-min-microvolt = <1200000>;
 				regulator-max-microvolt = <1350000>;
 				regulator-always-on;
 				regulator-initial-mode = <0>;