ARM: dts: stm32: fix pinctrl node name warnings (MCU soc)

The recent addition pinctrl.yaml in commit c09acbc4 ("dt-bindings:
pinctrl: use pinctrl.yaml") resulted in some node name warnings.
Fix the node names to the preferred 'pinctrl'.
Signed-off-by: Fabien Dessenne <fabien.dessenne@foss.st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/boot/dts/stm32f4-pinctrl.dtsi

@@ -45,7 +45,7 @@
 
 / {
 	soc {
-		pinctrl: pin-controller@40020000 {
+		pinctrl: pinctrl@40020000 {
 			#address-cells = <1>;
 			#size-cells = <1>;
 			ranges = <0 0x40020000 0x3000>;

arch/arm/boot/dts/stm32f7-pinctrl.dtsi

@@ -9,7 +9,7 @@
 
 / {
 	soc {
-		pinctrl: pin-controller@40020000 {
+		pinctrl: pinctrl@40020000 {
 			#address-cells = <1>;
 			#size-cells = <1>;
 			ranges = <0 0x40020000 0x3000>;

arch/arm/boot/dts/stm32h743.dtsi

@@ -583,7 +583,7 @@ mac: ethernet@40028000 {
 			status = "disabled";
 		};
 
-		pinctrl: pin-controller@58020000 {
+		pinctrl: pinctrl@58020000 {
 			#address-cells = <1>;
 			#size-cells = <1>;
 			compatible = "st,stm32h743-pinctrl";