HID: add __init/__exit macros to twinhan.c

Trivial patch which adds the __init/__exit macros to the module_init/
module_exit functions of the twinhan driver in hid.

Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>