staging: comedi: usbduxfast: fix a > 80 char line issue

Fix a line over 80 characters issue reported by checkpatch.pl.

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