Bluetooth: coredump: Quiesce dump work on unregister

In the Linux kernel, the following vulnerability has been resolved: Bluetooth: coredump: Quiesce dump work on unregister hci_devcd_handle_pkt_init() arms dump_timeout and coredump producers queue dump_rx without holding an hdev reference. Unregister leaves both works live, so disconnecting during an active dump lets them access hdev after hci_release_dev() frees it. Shut down coredump processing during unregister. Close the producer gate under dump_q.lock before disabling both works, then free the active buffer and queued packets under hci_dev_lock. Serializing the gate with enqueue prevents controller-specific workers from adding packets after the final purge.

Where it's fixed