thermal/drivers/core: Remove the module Kconfig's option

The module support for the thermal subsystem makes little sense:
 - some subsystems relying on it are not modules, thus forcing the
   framework to be compiled in
 - it is compiled in for almost every configs, the remaining ones
   are a few platforms where I don't see why we can not switch the thermal
   to 'y'. The drivers can stay in tristate.
 - platforms need the thermal to be ready as soon as possible at boot time
   in order to mitigate

Usually the subsystems framework are compiled-in and the plugs are as
module.

Remove the module option. The removal of the module related dead code will
come after this patch gets in or is acked.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Acked-by: Guenter Roeck <groeck@chromium.org>
For mini2440:
Acked-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Paul Burton <paul.burton@mips.com> # MIPS part
Acked-by: Robert Jarzmik <robert.jarzmik@free.fr>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>