arm64: dts: marvell: armada-3720-db: Add vqmmc regulator for SD slot

By adding this regulator, the SD cards are usable at higher speed
protocols such as SDR104.

This patch was tested with an SD HC card compatible with UHS-I.
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>

arch/arm64/boot/dts/marvell/armada-3720-db.dts

@@ -80,6 +80,20 @@ usb3_phy: usb3-phy {
 		compatible = "usb-nop-xceiv";
 		vcc-supply = <&exp_usb3_vbus>;
 	};
+
+	vcc_sd_reg1: regulator {
+		compatible = "regulator-gpio";
+		regulator-name = "vcc_sd1";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <3300000>;
+		regulator-boot-on;
+
+		gpios = <&gpiosb 23 GPIO_ACTIVE_HIGH>;
+		gpios-states = <0>;
+		states = <1800000 0x1
+			  3300000 0x0>;
+		enable-active-high;
+	};
 };
 
 /* Gigabit module on CON19(V2.0)/CON21(V1.4) */
@@ -164,6 +178,7 @@ &sdhci1 {
 	cd-gpios = <&gpiosb 2 GPIO_ACTIVE_LOW>;
 	bus-width = <4>;
 	marvell,pad-type = "sd";
+	vqmmc-supply = <&vcc_sd_reg1>;
 	status = "okay";
 };