int340X/processor_thermal_device: Fix proc_thermal_rapl_remove()

Passing 0 to cpuhp_remove_state() triggers the BUG_ON() in
__cpuhp_remove_state_cpuslocked() and the argument passed to
powercap_unregister_control_type() is expected to be a valid
pointer, so avoid calling these functions with incorrect
arguments from proc_thermal_rapl_remove().

Fixes: 555c45fe ("int340X/processor_thermal_device: add support for MMIO RAPL")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>