Generic Thermal Sysfs driver offers a generic mechanism for thermal management. Usually it's made up of one or more thermal zone and cooling device. Each thermal zone contains its own temperature, trip points, cooling devices. All platforms with ACPI thermal support can use this driver. If you want this support, you should say Y or M here.
The generic thermal sysfs driver's hardware monitoring support requires a 2.10.7/3.0.2 or later lm-sensors userspace. Say Y if your user-space is new enough.