dgnc: Make all lines under 80 characters in dgnc_driver.c

Some of the lines are over 80 characters in dgnc_driver.c so fix them by
moving the comments closer to the code, tidying the comments to make
them smaller, and remove a redundant space after +.

Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>