USB: option: blacklist network interface on Huawei E1820

commit b8a24e6281d37243c06b9497dcbfaa98c1e2ad35 upstream.

The mode used by Windows for the Huawei E1820 will use the
same ff/ff/ff class codes for both serial and network
functions.

Reported-by: Graham Inggs <graham.inggs@uct.ac.za>
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>