hwmon: (it87) Invalidate cache on temperature sensor change

When any temperature sensor type is changed, the corresponding
temperature value needs to be updated. The register caching mechanism
may delay this update, so we want to invalidate the cache to force an
immediate update.
Signed-off-by: NJean Delvare <khali@linux-fr.org>

drivers/hwmon/it87.c

@@ -563,6 +563,7 @@ static ssize_t set_sensor(struct device *dev, struct device_attribute *attr,
 	mutex_lock(&data->update_lock);
 	data->sensor = reg;
 	it87_write_value(data, IT87_REG_TEMP_ENABLE, data->sensor);
+	data->valid = 0;	/* Force cache refresh */
 	mutex_unlock(&data->update_lock);
 	return count;
 }