When upgrading from ar71xx target images to ath79 based ones, the
integrated wireless interface changes its sysfs path. Therefore the
previous enabled wireless interface will be disabled, which can cause
false complains about it not working. This commit adds hotplug event
which migrates to new path and will keep the wrireless interface
enabled after upgrade.
Signed-off-by: Tomasz Maciej Nowak <tomek_n@o2.pl>
