HID: hid-lenovo-go: cancel cfg_setup work in hid_go_cfg_remove()

Summary

In the Linux kernel, the following vulnerability has been resolved: HID: hid-lenovo-go: cancel cfg_setup work in hid_go_cfg_remove() hid_go_cfg_probe() initialises drvdata.go_cfg_setup and schedules it to run 2 ms later: INIT_DELAYED_WORK(&drvdata.go_cfg_setup, &cfg_setup); schedule_delayed_work(&drvdata.go_cfg_setup, msecs_to_jiffies(2)); cfg_setup() dereferences drvdata.hdev to issue MCU command requests. hid_go_cfg_remove() tears down sysfs and stops the HID device, but never drains the delayed work. If the device is unbound within the 2 ms scheduling delay (a probe failure rolling back via remove, or a fast rmmod after probe), the work fires after hid_destroy_device() has dropped its reference and released the underlying hdev struct, leaving cfg_setup() with a stale drvdata.hdev pointer. Mirror the sibling driver hid-lenovo-go-s.c, whose hid_gos_cfg_remove() already calls cancel_delayed_work_sync() on its analogous work, and drain go_cfg_setup at the top of hid_go_cfg_remove(). The cancel must come before guard(mutex)(&drvdata.cfg_mutex) because cfg_setup() acquires that mutex; reversing the order would deadlock.