It is usually possible to configure the polarity, cycle and duty all at
once, so that the polarity and cycle and duty are applied atomically.
Move it from rockchip_pwm_set_enable() into rockchip_pwm_config(), as
well as prepare for the next atomic update commit.
Signed-off-by: David Wu <david.wu@rock-chips.com> Signed-off-by: Thierry Reding <thierry.reding@gmail.com>