pwm: gpio: Switch to use hrtimer_setup()

hrtimer_setup() takes the callback function pointer as argument and
initializes the timer completely.

Replace hrtimer_init() and the open coded initialization of
hrtimer::function with the new setup mechanism.

Acked-by: Zack Rusin <[e-mail]>
Signed-off-by: Nam Cao <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>

drivers/pwm/pwm-gpio.c

···
 	chip->ops = &pwm_gpio_ops;
 	chip->atomic = true;
 
-	hrtimer_init(&gpwm->gpio_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	hrtimer_setup(&gpwm->gpio_timer, pwm_gpio_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+
 	ret = devm_add_action_or_reset(dev, pwm_gpio_disable_hrtimer, gpwm);
 	if (ret)
 		return ret;
-
-	gpwm->gpio_timer.function = pwm_gpio_timer;
 
 	ret = pwmchip_add(chip);
 	if (ret < 0)