pwm: Return -EINVAL for old-style drivers without .set_polarity callback

Since commit 2b1c1a5d ("pwm: Use -EINVAL for unsupported polarity")
all drivers implementing the apply callback are unified to return
-EINVAL if an unsupported polarity is requested. Do the same in the
compat code for old-style drivers.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/core.c

@@ -596,7 +596,7 @@ int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state)
 		 */
 		if (state->polarity != pwm->state.polarity) {
 			if (!chip->ops->set_polarity)
-				return -ENOTSUPP;
+				return -EINVAL;
 
 			/*
 			 * Changing the polarity of a running PWM is