ieee802154: cc2520: fix FIFOP work use-after-free

In the Linux kernel, the following vulnerability has been resolved: ieee802154: cc2520: fix FIFOP work use-after-free The FIFOP interrupt handler queues cc2520_fifop_irqwork. On removal, cc2520_remove() only flushes the work. The devm-managed FIFOP IRQ remains active until after ->remove() returns and can queue the work again after that flush, allowing it to run after the private data is released. Disable the work with disable_work_sync() instead of flushing it, so the handler can no longer queue it once removal begins. Destroy the buffer mutex last, since the worker and the stop callback invoked through ieee802154_unregister_hw() both take it. Found by an in-house static analysis tool.

Where it's fixed