hwmon: (adt7462) Fix an error return in ADT7462_REG_VOLT()

This is only called from adt7462_update_device().  The caller expects it
to return zero on error.  I fixed a similar issue earlier in commit
a4bf06d58f ("hwmon: (adt7462) ADT7462_REG_VOLT_MAX() should return 0")
but I missed this one.

Fixes: c0b4e3ab0c ("adt7462: new hwmon driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Link: https://lore.kernel.org/r/20200303101608.kqjwfcazu2ylhi2a@kili.mountain
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/hwmon/adt7462.c

@@ -413,7 +413,7 @@ static int ADT7462_REG_VOLT(struct adt7462_data *data, int which)
 			return 0x95;
 		break;
 	}
-	return -ENODEV;
+	return 0;
 }
 
 /* Provide labels for sysfs */