pwm: lpc18xx-sct: Drop driver local locking

Both mutexes are only used in one function each. These functions are only
called by the .apply() callback. As the .apply() calls are serialized by
the core since commit 1cc2e1faafb3 ("pwm: Add more locking") the mutexes
have no effect apart from runtime overhead. Drop them.

Signed-off-by: Uwe Kleine-König <[e-mail]>
Reviewed-by: Vladimir Zapolskiy <[e-mail]>
Link: https://lore.kernel.org/r/4f7a2da[e-mail]
Signed-off-by: Uwe Kleine-König <[e-mail]>

drivers/pwm/pwm-lpc18xx-sct.c

···
 	u64 max_period_ns;
 	unsigned int period_event;
 	unsigned long event_map;
-	struct mutex res_lock;
-	struct mutex period_lock;
 	struct lpc18xx_pwm_data channeldata[LPC18XX_NUM_PWMS];
 };
 
···
 {
 	u32 val;
 
-	mutex_lock(&lpc18xx_pwm->res_lock);
-
 	/*
 	 * Simultaneous set and clear may happen on an output, that is the case
 	 * when duty_ns == period_ns. LPC18xx SCT allows to set a conflict
···
 	val &= ~LPC18XX_PWM_RES_MASK(pwm->hwpwm);
 	val |= LPC18XX_PWM_RES(pwm->hwpwm, action);
 	lpc18xx_pwm_writel(lpc18xx_pwm, LPC18XX_PWM_RES_BASE, val);
-
-	mutex_unlock(&lpc18xx_pwm->res_lock);
 }
 
 static void lpc18xx_pwm_config_period(struct pwm_chip *chip, u64 period_ns)
···
 		return -ERANGE;
 	}
 
-	mutex_lock(&lpc18xx_pwm->period_lock);
-
 	requested_events = bitmap_weight(&lpc18xx_pwm->event_map,
 					 LPC18XX_PWM_EVENT_MAX);
 
···
 	    lpc18xx_pwm->period_ns) {
 		dev_err(pwmchip_parent(chip), "conflicting period requested for PWM %u\n",
 			pwm->hwpwm);
-		mutex_unlock(&lpc18xx_pwm->period_lock);
 		return -EBUSY;
 	}
 
···
 		lpc18xx_pwm->period_ns = period_ns;
 		lpc18xx_pwm_config_period(chip, period_ns);
 	}
-
-	mutex_unlock(&lpc18xx_pwm->period_lock);
 
 	lpc18xx_pwm_config_duty(chip, pwm, duty_ns);
 
···
 	 */
 	if (lpc18xx_pwm->clk_rate > NSEC_PER_SEC)
 		return dev_err_probe(&pdev->dev, -EINVAL, "pwm clock to fast\n");
-
-	mutex_init(&lpc18xx_pwm->res_lock);
-	mutex_init(&lpc18xx_pwm->period_lock);
 
 	lpc18xx_pwm->max_period_ns =
 		mul_u64_u64_div_u64(NSEC_PER_SEC, LPC18XX_PWM_TIMER_MAX, lpc18xx_pwm->clk_rate);