hwmon: (lm90) Use bool for valid flag

Use bool for valid flag and leave it up to the compiler to find
an optimal representation.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/lm90.c

@@ -367,7 +367,7 @@ struct lm90_data {
 	struct i2c_client *client;
 	const struct attribute_group *groups[6];
 	struct mutex update_lock;
-	char valid; /* zero until following fields are valid */
+	bool valid;		/* true if register values are valid */
 	unsigned long last_updated; /* in jiffies */
 	int kind;
 	u32 flags;
@@ -624,7 +624,7 @@ static struct lm90_data *lm90_update_device(struct device *dev)
 	if (time_after(jiffies, next_update) || !data->valid) {
 		dev_dbg(&client->dev, "Updating lm90 data.\n");
 
-		data->valid = 0;
+		data->valid = false;
 
 		val = lm90_read_reg(client, LM90_REG_R_LOCAL_LOW);
 		if (val < 0)
@@ -697,7 +697,7 @@ static struct lm90_data *lm90_update_device(struct device *dev)
 		}
 
 		data->last_updated = jiffies;
-		data->valid = 1;
+		data->valid = true;
 	}
 
 error: