ARM: dts: stm32: Define VIO regulator supply on DHCOM

The VIO regulator is supplied by PMIC Buck3, describe this in the DT.

Fixes: 34e0c784 ("ARM: dts: stm32: Add DH Electronics DHCOM STM32MP1 SoM and PDK2 board")
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp15xx-dhcom-som.dtsi

@@ -68,6 +68,7 @@ ethernet_vio: vioregulator {
 		gpio = <&gpiog 3 GPIO_ACTIVE_LOW>;
 		regulator-always-on;
 		regulator-boot-on;
+		vin-supply = <&vdd>;
 	};
 };