pwm: imx27: Make use of pwmchip_parent() accessor

struct pwm_chip::dev is about to change. To not have to touch this
driver in the same commit as struct pwm_chip::dev, use the accessor
function provided for exactly this purpose.

Link: https://lore.kernel.org/r/a8e3e3b3ea0684c9b289999c6f09eedbc2520f54.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-imx27.c

@@ -145,7 +145,7 @@ static int pwm_imx27_get_state(struct pwm_chip *chip,
 		state->polarity = PWM_POLARITY_INVERSED;
 		break;
 	default:
-		dev_warn(chip->dev, "can't set polarity, output disconnected");
+		dev_warn(pwmchip_parent(chip), "can't set polarity, output disconnected");
 	}
 
 	prescaler = MX3_PWMCR_PRESCALER_GET(val);
@@ -177,7 +177,7 @@ static int pwm_imx27_get_state(struct pwm_chip *chip,
 static void pwm_imx27_sw_reset(struct pwm_chip *chip)
 {
 	struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
-	struct device *dev = chip->dev;
+	struct device *dev = pwmchip_parent(chip);
 	int wait_count = 0;
 	u32 cr;
 
@@ -196,7 +196,7 @@ static void pwm_imx27_wait_fifo_slot(struct pwm_chip *chip,
 				     struct pwm_device *pwm)
 {
 	struct pwm_imx27_chip *imx = to_pwm_imx27_chip(chip);
-	struct device *dev = chip->dev;
+	struct device *dev = pwmchip_parent(chip);
 	unsigned int period_ms;
 	int fifoav;
 	u32 sr;