staging: comedi: ni_tio.h: fix block comment

Fix the checkpatch.pl issue:
WARNING: Block comments use * on subsequent lines

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>