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>