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

The recent addition pinctrl.yaml in commit c09acbc499e8 ("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 <[e-mail]>
Signed-off-by: Alexandre Torgue <[e-mail]>

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

···
 
 / {
 	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

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

arch/arm/boot/dts/stm32h743.dtsi

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