hwmon: (lm90) use proper type for update_interval

The code handles this variable always as unsigned, so adapt the type.
Signed-off-by: NWolfram Sang <wsa@the-dreams.de>
Signed-off-by: NGuenter Roeck <linux@roeck-us.net>

drivers/hwmon/lm90.c

@@ -375,7 +375,7 @@ struct lm90_data {
 	int kind;
 	u32 flags;
 
-	int update_interval;	/* in milliseconds */
+	unsigned int update_interval; /* in milliseconds */
 
 	u8 config_orig;		/* Original configuration register value */
 	u8 convrate_orig;	/* Original conversion rate register value */