pwm: lpss: Allow duty cycle to be 0

A duty cycle is represented by values [0..<period>] which reflects [0%..100%].
0% of the duty cycle means always off (logical "0") on output. Allow this in
the driver.
Reviewed-by: NMika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: NAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: NThierry Reding <thierry.reding@gmail.com>

drivers/pwm/pwm-lpss.c

@@ -107,8 +107,6 @@ static int pwm_lpss_config(struct pwm_chip *chip, struct pwm_device *pwm,
 
 	base_unit = DIV_ROUND_CLOSEST_ULL(freq, c);
 
-	if (duty_ns <= 0)
-		duty_ns = 1;
 	on_time_div = 255ULL * duty_ns;
 	do_div(on_time_div, period_ns);
 	on_time_div = 255ULL - on_time_div;