MAINTAINERS: USB, remove F: drivers/net/usb/ pattern

On Tue, 2013-07-30 at 06:58 -0700, Greg KH wrote:

> In the future, you do not need to send drivers/net/usb/ patches to me,
> netdev and the linux-usb mailing lists should be sufficient.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>