The netlink event processing is delayed since they are only returned
after control returns to eloop. This can result in netlink down events
being processed at a point when the interface has is actually still
there (the first event on new interface is down) and that can result in
odd behavior especially when the resulting interface-disabled event is
delivered to AP mode interface with wpa_supplicant.
Work around this by filtering netlink down events if the matching
interface is up at the time the netlink event is processed. This fixes
an issue brought up by commit 36d84860bb.