pwm: Make pwmchip_[sg]et_drvdata() a wrapper around dev_set_drvdata()

Now that a pwm_chip has a dedicated struct device, pwmchip_set_drvdata()
and pwmchip_get_drvdata() can be made thin wrappers around
dev_set_drvdata() and dev_get_drvdata() respectively and the previously
needed pointer can be dropped from struct pwm_chip.

Link: https://lore.kernel.org/r/a5e05bd2d83421a26fdef6a87d69253c0f98becf.1710670958.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

include/linux/pwm.h

@@ -274,7 +274,6 @@ struct pwm_ops {
  * @of_xlate: request a PWM device given a device tree PWM specifier
  * @atomic: can the driver's ->apply() be called in atomic context
  * @uses_pwmchip_alloc: signals if pwmchip_allow was used to allocate this chip
- * @driver_data: Private pointer for driver specific info
  * @pwms: array of PWM devices allocated by the framework
  */
 struct pwm_chip {
@@ -290,7 +289,6 @@ struct pwm_chip {
 
 	/* only used internally by the PWM framework */
 	bool uses_pwmchip_alloc;
-	void *driver_data;
 	struct pwm_device pwms[] __counted_by(npwm);
 };
 
@@ -301,20 +299,12 @@ static inline struct device *pwmchip_parent(const struct pwm_chip *chip)
 
 static inline void *pwmchip_get_drvdata(struct pwm_chip *chip)
 {
-	/*
-	 * After pwm_chip got a dedicated struct device, this can be replaced by
-	 * dev_get_drvdata(&chip->dev);
-	 */
-	return chip->driver_data;
+	return dev_get_drvdata(&chip->dev);
 }
 
 static inline void pwmchip_set_drvdata(struct pwm_chip *chip, void *data)
 {
-	/*
-	 * After pwm_chip got a dedicated struct device, this can be replaced by
-	 * dev_set_drvdata(&chip->dev, data);
-	 */
-	chip->driver_data = data;
+	dev_set_drvdata(&chip->dev, data);
 }
 
 #if IS_ENABLED(CONFIG_PWM)