HID: wacom: fix crash in wacom_aes_battery_handler()

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

HID: wacom: fix crash in wacom_aes_battery_handler()

Commit fd2a9b29dc9c ("HID: wacom: Remove AES power_supply after extended inactivity") introduced wacom_aes_battery_handler() which is scheduled as a delayed work (aes_battery_work).

In wacom_remove(), aes_battery_work is not canceled. Consequently, if the device is removed while aes_battery_work is still pending, then hard crashes or "Oops: general protection fault..." are experienced when wacom_aes_battery_handler() is finally called. E.g., this happens with built-in USB devices after resume from hibernate when aes_battery_work was still pending at the time of hibernation.

So, take care to cancel aes_battery_work in wacom_remove().