thermal: cpu_cooling: update Kconfig entry

There is no support for hotplug or any other means of reducing
temperature. So, this patch removes these references from Kconfig.

Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Acked-by: Amit Daniel Kachhap <amit.daniel@samsung.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>