ARM: dts: stm32: Correct stmfx node name on stm32mp157c-ev1 board

Change stmfx node name to fit with yaml requirements.
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157c-ev1.dts

@@ -210,7 +210,7 @@ stmfx: stmfx@42 {
 		interrupt-parent = <&gpioi>;
 		vdd-supply = <&v3v3>;
 
-		stmfx_pinctrl: stmfx-pin-controller {
+		stmfx_pinctrl: pinctrl {
 			compatible = "st,stmfx-0300-pinctrl";
 			gpio-controller;
 			#gpio-cells = <2>;