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/w83781d.c b/drivers/hwmon/w83781d.c
index dcc941a..8ed88f3 100644
--- a/drivers/hwmon/w83781d.c
+++ b/drivers/hwmon/w83781d.c
@@ -410,7 +410,7 @@
 	struct sensor_device_attribute *attr = to_sensor_dev_attr(da); \
 	struct w83781d_data *data = dev_get_drvdata(dev); \
 	int nr = attr->index; \
-	s32 val; \
+	long val; \
 	 \
 	val = simple_strtol(buf, NULL, 10); \
 	 \