Bluetooth: fix memory leak in error path of hci_alloc_dev()

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: fix memory leak in error path of hci_alloc_dev()

Early failures in Bluetooth HCI UART configuration leak SRCU percpu

memory.

When device initialization fails before hci_register_dev() completes,

the HCI_UNREGISTER flag is never set. As a result, when the device

reference count reaches zero, bt_host_release() evaluates this flag as

false and falls back to a direct kfree(hdev).

Because hci_release_dev() is bypassed, the SRCU struct initialized

early in hci_alloc_dev() is never cleaned up, resulting in a leak of

percpu memory.

Fix the leak by explicitly calling cleanup_srcu_struct() in the

fallback (unregistered) branch of bt_host_release() before freeing

the device.