[PATCH] hwmon: Fix unsigned 'reg' compared with zero in amc6821_update_device

[xiakaixu1987]

From: Kaixu Xia <kaixuxia@xxxxxxxxxxx>

The unsigned variable reg is assigned a return value from the call
to i2c_smbus_read_byte_data(), which may return negative error code.

Fixes coccicheck warning:

./drivers/hwmon/amc6821.c:215:6-9: WARNING: Unsigned expression compared with zero: reg > 0
./drivers/hwmon/amc6821.c:228:6-9: WARNING: Unsigned expression compared with zero: reg > 0

Reported-by: Tosk Robot <tencent_os_robot@xxxxxxxxxxx>
Signed-off-by: Kaixu Xia <kaixuxia@xxxxxxxxxxx>
---
 drivers/hwmon/amc6821.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/amc6821.c b/drivers/hwmon/amc6821.c
index 6b1ce2242c61..ce7c9f412538 100644
--- a/drivers/hwmon/amc6821.c
+++ b/drivers/hwmon/amc6821.c
@@ -166,7 +166,7 @@ static struct amc6821_data *amc6821_update_device(struct device *dev)
 	struct amc6821_data *data = dev_get_drvdata(dev);
 	struct i2c_client *client = data->client;
 	int timeout = HZ;
-	u8 reg;
+	s8 reg;
 	int i;
 
 	mutex_lock(&data->update_lock);
-- 
2.20.0