arm64: dts: imx8mq-evk: VDD_ARM power rail is always ON

On i.MX8MQ EVK board, VDD_ARM is from a DC-DC converter which
is always ON, the GPIO1_IO13 is ONLY to switch VDD_ARM's voltage
between 0.9V and 1V for CPU DVFS, so VDD_ARM's GPIO regulator
should be always ON to avoid below confusion after kernel boot
up:

imx8mqevk login:
[   31.776619] vdd_arm: disabling
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-evk.dts

@@ -48,6 +48,8 @@ buck2_reg: regulator-buck2 {
 		gpios = <&gpio1 13 GPIO_ACTIVE_HIGH>;
 		states = <1000000 0x0
 			  900000 0x1>;
+		regulator-boot-on;
+		regulator-always-on;
 	};
 
 	wm8524: audio-codec {