arm64: dts: freescale: imx8mp-verdin: Fix SD regulator startup delay

The power switch used to power the SD card interface might have
more than 2ms turn-on time, increase the startup delay to 20ms to
prevent failures.

Fixes: a39ed23bdf6e ("arm64: dts: freescale: add initial support for verdin imx8m plus")
Cc: [e-mail]
Signed-off-by: Francesco Dolcini <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm64/boot/dts/freescale/imx8mp-verdin.dtsi

···
 		regulator-max-microvolt = <3300000>;
 		regulator-min-microvolt = <3300000>;
 		regulator-name = "+V3.3_SD";
-		startup-delay-us = <2000>;
+		startup-delay-us = <20000>;
 	};
 
 	reserved-memory {