pwm: tiehrpwm: Simplify code to determine the pwmchip's parent device

There is already a pointer to the pwmchip, make use of it directly
instead of using the struct ehrpwm_pwm_chip *ddata just obtained from
it. This also has the advantage of not using struct
ehrpwm_pwm_chip::chip any more which will be dropped soon.

Link: https://lore.kernel.org/r/b2b06a3aabf8c04969d59ddf7ba565b303855878.1707900770.git.u.kleine-koenig@pengutronix.deSigned-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>

drivers/pwm/pwm-tiehrpwm.c

@@ -347,7 +347,7 @@ static int ehrpwm_pwm_enable(struct pwm_chip *chip, struct pwm_device *pwm)
 	ret = clk_enable(pc->tbclk);
 	if (ret) {
 		dev_err(chip->dev, "Failed to enable TBCLK for %s: %d\n",
-			dev_name(pc->chip.dev), ret);
+			dev_name(chip->dev), ret);
 		return ret;
 	}