ARM: dts: stm32: enable USBPHYC on stm32mp15 DKx boards

This patch enables USBPHYC (USB PHY Controller on stm32mp15 DKx boards.
This enables the two usbphyc usb2 ports, which require 3 supplies:
3v3, 1v1 and 1v8.
Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp15xx-dkx.dtsi

@@ -589,6 +589,22 @@ &uart4 {
 	status = "okay";
 };
 
+&usbphyc {
+	status = "okay";
+};
+
+&usbphyc_port0 {
+	phy-supply = <&vdd_usb>;
+	vdda1v1-supply = <&reg11>;
+	vdda1v8-supply = <&reg18>;
+};
+
+&usbphyc_port1 {
+	phy-supply = <&vdd_usb>;
+	vdda1v1-supply = <&reg11>;
+	vdda1v8-supply = <&reg18>;
+};
+
 &vrefbuf {
 	regulator-min-microvolt = <2500000>;
 	regulator-max-microvolt = <2500000>;