Re: divide error in usbnet_update_max_qlen

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger  
crash:

Reported-and-tested-by:  
syzbot+6102c120be558c885f04@xxxxxxxxxxxxxxxxxxxxxxxxx

Tested on:

commit:         f0df5c1b usb-fuzzer: main usb gadget fuzzer driver
git tree:       https://github.com/google/kasan.git
kernel config:  https://syzkaller.appspot.com/x/.config?x=5c6633fa4ed00be5
dashboard link: https://syzkaller.appspot.com/bug?extid=6102c120be558c885f04
compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
patch:          https://syzkaller.appspot.com/x/patch.diff?x=148689be600000

Note: testing is done by a robot and is best-effort only.