controllers. sk(4) never reprogrammed station address for Yukon
controllers so overriding station address with ifconfig(8) was not
possible.
Fix the bug by reprogramming all registers that control station
address, flow-control and virtual station address. Virtual station
address has no use at this moment since driver does not make use of
fail over feature.
Tested by: "Mikhail T." <mi+thun <> aldan.algebra.com>
MFC after: 1 week
fec5229ac0