Staging: comedi: kcomedilib: Add module_init/exit function

Add init/exit function to follow LKM semantics.
Apparently this module can still load/unload without
the init/exit function.

Tested loading/unloading with and without this patch.

Signed-off-by: Cheah Kok Cheong <thrust73@gmail.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>