pwm: Drop per-chip dbg_show callback

This callback was introduced in commit 62099abf ("pwm: Add debugfs
interface") in 2012 and up to now there is not a single user. So drop
this unused code.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
[thierry.reding@gmail.com: remove kerneldoc for ->dbg_show()]
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/core.c

@@ -1036,9 +1036,6 @@ static int pwm_seq_show(struct seq_file *s, void *v)
 		   dev_name(chip->dev), chip->npwm,
 		   (chip->npwm != 1) ? "s" : "");
 
-	if (chip->ops->dbg_show)
-		chip->ops->dbg_show(chip, s);
-	else
 	pwm_dbg_show(chip, s);
 
 	return 0;

include/linux/pwm.h

@@ -254,7 +254,6 @@ pwm_set_relative_duty_cycle(struct pwm_state *state, unsigned int duty_cycle,
  * @get_state: get the current PWM state. This function is only
  *	       called once per PWM device when the PWM chip is
  *	       registered.
- * @dbg_show: optional routine to show contents in debugfs
  * @owner: helps prevent removal of modules exporting active PWMs
  */
 struct pwm_ops {
@@ -272,9 +271,6 @@ struct pwm_ops {
 		     struct pwm_state *state);
 	void (*get_state)(struct pwm_chip *chip, struct pwm_device *pwm,
 			  struct pwm_state *state);
-#ifdef CONFIG_DEBUG_FS
-	void (*dbg_show)(struct pwm_chip *chip, struct seq_file *s);
-#endif
 	struct module *owner;
 };