Input: appletouch - initialize work before device registration

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

Input: appletouch - initialize work before device registration

Syzbot has reported warning in __flush_work(). This warning is caused by

work->func == NULL, which means missing work initialization.

This may happen, since input_dev->close() calls

cancel_work_sync(&dev->work), but dev->work initalization happens _after_

input_register_device() call.

So this patch moves dev->work initialization before registering input

device