staging: vc04_services: vchiq_core: Stop kthreads on shutdown

The various kthreads thread functions (slot_handler_func, sync_func,
recycle_func) in vchiq_core and vchiq_keepalive_thread_func in
vchiq_arm should be stopped on vchiq_shutdown().

This also address the following TODO item:
 * Fix kernel module support

hence drop it from the TODO item list.

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Link: https://lore.kernel.org/r/20240321130737.898154-6-umang.jain@ideasonboard.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>