thermal: intel: intel_pch: Rename device operations callbacks

Because the same device operations callbacks are used for all supported
boards, they are in fact generic, so rename them to reflect that.

Also rename the operations object itself for consistency.

No intentional functional impact.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Tested-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Zhang Rui <rui.zhang@intel.com>