hwmon: (adt7475) Add missing static marker

adt7475_attr_group is used internally only and can thus be marked
static.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: Jordan Crouse <jordan@cosmicpenguin.net>
Cc: "Darrick J. Wong" <djwong@us.ibm.com>

drivers/hwmon/adt7475.c

@@ -1008,7 +1008,7 @@ static struct attribute *adt7475_attrs[] = {
 	NULL,
 };
 
-struct attribute_group adt7475_attr_group = { .attrs = adt7475_attrs };
+static struct attribute_group adt7475_attr_group = { .attrs = adt7475_attrs };
 
 static int adt7475_detect(struct i2c_client *client, int kind,
 			  struct i2c_board_info *info)