arm64: dts: rockchip: Fix min voltage for rk3399-firefly vdd_log

The min/max value of vdd_log is decide by pwm IO voltage and its
resistors, the rk3399-firefly board's pwm regulator circuit is designed
for IO voltage at 1.8V, while the board actually use 3.0V for IO, which
at last lead to the min-microvolt to '430mV' instead of '800mV'.
Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Link: https://lore.kernel.org/r/20191111005158.25070-1-kever.yang@rock-chips.comSigned-off-by: Heiko Stuebner <heiko@sntech.de>

arch/arm64/boot/dts/rockchip/rk3399-firefly.dts

@@ -206,7 +206,7 @@ vdd_log: vdd-log {
 		regulator-name = "vdd_log";
 		regulator-always-on;
 		regulator-boot-on;
-		regulator-min-microvolt = <800000>;
+		regulator-min-microvolt = <430000>;
 		regulator-max-microvolt = <1400000>;
 		vin-supply = <&vcc_sys>;
 	};