ramips: Fix drivers/pwm/pwm-mediatek-ramips.c compile

The pwmchip_remove() function returns void now. Fix a compile problem in
the drivers/pwm/pwm-mediatek-ramips.c driver.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

target/linux/ramips/patches-5.15/845-pwm-add-mediatek-support.patch

@@ -41,7 +41,7 @@ Signed-off-by: John Crispin <blogic@openwrt.org>
  obj-$(CONFIG_PWM_NTXEC)		+= pwm-ntxec.o
 --- /dev/null
 +++ b/drivers/pwm/pwm-mediatek-ramips.c
-@@ -0,0 +1,173 @@
+@@ -0,0 +1,175 @@
 +/*
 + * Mediatek Pulse Width Modulator driver
 + *
@@ -190,7 +190,9 @@ Signed-off-by: John Crispin <blogic@openwrt.org>
 +	for (i = 0; i < NUM_PWM; i++)
 +		pwm_disable(&pc->chip.pwms[i]);
 +
-+	return pwmchip_remove(&pc->chip);
++	pwmchip_remove(&pc->chip);
++
++	return 0;
 +}
 +
 +static const struct of_device_id mtk_pwm_of_match[] = {