usb: misc: adutux: fix whitespace coding style issue

Correct missing space error ceckpatch.pl is complaining about.

Signed-off-by: Malte Deiseroth <mdeiseroth88@gmail.com>
Link: https://lore.kernel.org/r/20210416080843.GA137657@utop


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>