staging: vc04_services: vchiq_core: Stop kthreads on vchiq module unload

staging: vc04_services: vchiq_core: Stop kthreads on vchiq module unload

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 when the module is unloaded.

Previous attempt were made to address this but later reverted [1]
due to VC04 firmware corruption. The issue around
wait_event_interruptible() handling on stopping a kthread has been
handled in the previous commit. Hence, it is now safe to stop kthreads
on module unload, without any firmware corruption.

This also completes the "Fix kernel module support" TODO item, hence
drop it from the list.

[1] commit ebee9ca2f59e ("Revert "staging: vc04_services: vchiq_core: Stop kthreads on shutdown"")

Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
Tested-by: Stefan Wahren <wahrenst@gmx.net>
Link: https://lore.kernel.org/r/20240703131052.597443-3-umang.jain@ideasonboard.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>