arm64: dts: imx8mp-var-som: Fix LDO5 shutdown causing SD card timeout

Fix SD card timeout issue caused by LDO5 regulator getting disabled
after boot.

The kernel log shows LDO5 being disabled, which leads to a timeout
on USDHC2:
[   33.760561] LDO5: disabling
[   81.119861] mmc1: Timeout waiting for hardware interrupt.

To prevent this, set regulator-boot-on and regulator-always-on for
LDO5. Also add the vqmmc regulator to properly support 1.8V/3.3V
signaling for USDHC2 using a GPIO-controlled regulator.

Fixes: 6c2a1f4 ("arm64: dts: imx8mp-var-som-symphony: Add Variscite Symphony board and VAR-SOM-MX8MP SoM")
Signed-off-by: Himanshu Bhavani <himanshu.bhavani@siliconsignals.io>
Acked-by: Tarang Raval <tarang.raval@siliconsignals.io>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mp-var-som.dtsi

@@ -35,7 +35,6 @@
 		      <0x1 0x00000000 0 0xc0000000>;
 	};
 
-
 	reg_usdhc2_vmmc: regulator-usdhc2-vmmc {
 	        compatible = "regulator-fixed";
 	        regulator-name = "VSD_3V3";
@@ -46,6 +45,16 @@
 	        startup-delay-us = <100>;
 	        off-on-delay-us = <12000>;
 	};
+
+	reg_usdhc2_vqmmc: regulator-usdhc2-vqmmc {
+		compatible = "regulator-gpio";
+		regulator-name = "VSD_VSEL";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <3300000>;
+		gpios = <&gpio2 12 GPIO_ACTIVE_HIGH>;
+		states = <3300000 0x0 1800000 0x1>;
+		vin-supply = <&ldo5>;
+	};
 };
 
 &A53_0 {
@@ -205,6 +214,7 @@
         pinctrl-2 = <&pinctrl_usdhc2_200mhz>, <&pinctrl_usdhc2_gpio>;
         cd-gpios = <&gpio1 14 GPIO_ACTIVE_LOW>;
         vmmc-supply = <&reg_usdhc2_vmmc>;
+	vqmmc-supply = <&reg_usdhc2_vqmmc>;
         bus-width = <4>;
         status = "okay";
 };