hwmon: Allow writing of negative trigger temperatures

- replace differing temperature variable types by long
- use strtol() instead of strtoul() for conversion

Signed-off-by: Christian Hohnstaedt <chohnstaedt@innominate.com>
Acked-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
diff --git a/drivers/hwmon/ad7418.c b/drivers/hwmon/ad7418.c
index cc8b624..879ea72 100644
--- a/drivers/hwmon/ad7418.c
+++ b/drivers/hwmon/ad7418.c
@@ -172,7 +172,7 @@
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
 	struct i2c_client *client = to_i2c_client(dev);
 	struct ad7418_data *data = i2c_get_clientdata(client);
-	int temp = simple_strtol(buf, NULL, 10);
+	long temp = simple_strtol(buf, NULL, 10);
 
 	mutex_lock(&data->lock);
 	data->temp[attr->index] = LM75_TEMP_TO_REG(temp);