pwm: sti: Drop driver local locking

The pwm core already serializes calls to .apply(), so the driver local
mutex adds no protection and can be dropped.

Signed-off-by: Uwe Kleine-König <[e-mail]>
Link: https://lore.kernel.org/r/7ad150e[e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>

drivers/pwm/pwm-sti.c

···
 	struct pwm_device *cur;
 	unsigned long configured;
 	unsigned int en_count;
-	struct mutex sti_pwm_lock; /* To sync between enable/disable calls */
 	void __iomem *mmio;
 };
 
···
 {
 	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 	struct device *dev = pc->dev;
-	int ret = 0;
+	int ret;
 
 	/*
 	 * Since we have a common enable for all PWM devices, do not enable if
 	 * already enabled.
 	 */
-	mutex_lock(&pc->sti_pwm_lock);
 
 	if (!pc->en_count) {
 		ret = clk_enable(pc->pwm_clk);
 		if (ret)
-			goto out;
+			return ret;
 
 		ret = clk_enable(pc->cpt_clk);
 		if (ret)
-			goto out;
+			return ret;
 
 		ret = regmap_field_write(pc->pwm_out_en, 1);
 		if (ret) {
 			dev_err(dev, "failed to enable PWM device %u: %d\n",
 				pwm->hwpwm, ret);
-			goto out;
+			return ret;
 		}
 	}
 
 	pc->en_count++;
 
-out:
-	mutex_unlock(&pc->sti_pwm_lock);
-	return ret;
+	return 0;
 }
 
 static void sti_pwm_disable(struct pwm_chip *chip, struct pwm_device *pwm)
 {
 	struct sti_pwm_chip *pc = to_sti_pwmchip(chip);
 
-	mutex_lock(&pc->sti_pwm_lock);
-
-	if (--pc->en_count) {
-		mutex_unlock(&pc->sti_pwm_lock);
+	if (--pc->en_count)
 		return;
-	}
 
 	regmap_field_write(pc->pwm_out_en, 0);
 
 	clk_disable(pc->pwm_clk);
 	clk_disable(pc->cpt_clk);
-
-	mutex_unlock(&pc->sti_pwm_lock);
 }
 
 static void sti_pwm_free(struct pwm_chip *chip, struct pwm_device *pwm)
···
 
 	pc->dev = dev;
 	pc->en_count = 0;
-	mutex_init(&pc->sti_pwm_lock);
 
 	ret = sti_pwm_probe_regmap(pc);
 	if (ret)