This converts the drivers in drivers/net/* to use the
module_usb_driver() macro which makes the code smaller and a bit
simpler.

Added bonus is that it removes some unneeded kernel log messages about
drivers loading and/or unloading.

Cc: Wolfgang Grandegger <wg@grandegger.com>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: Oliver Neukum <oliver@neukum.name>
Cc: Peter Korsgaard <jacmet@sunsite.dk>
Cc: Petko Manolov <petkan@users.sourceforge.net>
Cc: Steve Glendinning <steve.glendinning@smsc.com>
Cc: Christian Lamparter <chunkeey@googlemail.com>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Cc: Ivo van Doorn <IvDoorn@gmail.com>
Cc: Gertjan van Wingerde <gwingerde@gmail.com>
Cc: Helmut Schaa <helmut.schaa@googlemail.com>
Cc: Herton Ronaldo Krzesinski <herton@canonical.com>
Cc: Hin-Tak Leung <htl10@users.sourceforge.net>
Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Chaoming Li <chaoming_li@realsil.com.cn>
Cc: Lucas De Marchi <lucas.demarchi@profusion.mobi>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Roel Kluin <roel.kluin@gmail.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Jiri Pirko <jpirko@redhat.com>
Cc: Pavel Roskin <proski@gnu.org>
Cc: Yoann DI-RUZZA <y.diruzza@lim.eu>
Cc: George <george0505@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>