power: fan53555: fix fan53555_regulator_set_value

fan53555_regulator_set_value() passes its own dev to pmic_clrsetbits()
instead of its parent (pmic). As result u-boot crashes when you try to
set voltage on fan53555 regulator

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>