drivers: pwm: stm32: Catch overflows in 2-channel capture

When not using 4 channel capture, overflows were never reported
to the application, because the check was in the
four_channel_capture_support branch.

Signed-off-by: Fabian Pflug <fabian.pflug@grandcentrix.net>

drivers/pwm/pwm_stm32.c

@@ -732,12 +732,12 @@ static void pwm_stm32_isr(const struct device *dev)
 			/* Still waiting for a complete capture */
 			return;
 		}
+	}
 
 	if (cpt->overflows) {
 		LOG_ERR("counter overflow during PWM capture");
 		status = -ERANGE;
 	}
-	}
 
 	if (!cpt->continuous) {
 		pwm_stm32_disable_capture(dev, cpt->channel);