staging: comedi: pcmuio: fix > 80 char line warnings

Cleanup some comments to fix the checkpatch.pl warnings about lines
over 80 characters.

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>