arm64: dts: mediatek: mt8186-evb: Add vproc fixed regulator

This board at the moment has no support for PMIC regulators, but
the CCI requires a vproc regulator in order to both stop giving
dtbs_check warnings and to actually probe.

Since vproc is a system-critical regulator and the bootloader
enables it at max voltage, model it (at least temporarily) as
a regulator-fixed and assign it to CCI.

Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Author: AngeloGioacchino Del Regno

arch/arm64/boot/dts/mediatek/mt8186-evb.dts

@@ -22,6 +22,19 @@
 		device_type = "memory";
 		reg = <0 0x40000000 0 0x80000000>;
 	};
+
+	vproc: regulator-vproc12 {
+		compatible = "regulator-fixed";
+		regulator-name = "vproc12";
+		regulator-always-on;
+		regulator-boot-on;
+		regulator-min-microvolt = <1200000>;
+		regulator-max-microvolt = <1200000>;
+	};
+};
+
+&cci {
+	proc-supply = <&vproc>;
 };
 
 &i2c0 {