CVE-2026-98311: wifi: virt_wifi: don't transfer operstate before register

In the Linux kernel, the following vulnerability has been resolved:

wifi: virtwifi: don't transfer operstate before register

virtwifinewlink() calls netifstackedtransferoperstate() before registernetdevice(). If the lower device is dormant, that queues the new netdev on lweventlist while it is still uninitialized. If registration fails after that, for example because of an invalid name such as "bad/name", freenetdev() immediately frees the object. A later linkwatchfireevent() then use-after-frees the list entry.

Move the transfer to after netdevupperdevlink(), as macvlan and ipvlan already do.