Removing period, duty and polarity configuration from
channel devicetree. At boot time, only minimal setup like
pinctrl, prescaler, etc should be initialized. PWM signal
is produced by using pwm_set* API
Also after this change, PWM period, duty are changed at the
next counter period boundary
Signed-off-by: Dat Nguyen Duy <dat.nguyenduy@nxp.com>