hostapd: add owe_transition_ifname

hostapd: add owe_transition_ifname

Add the owe_transition_ifname config option to wifi-ifaces.

This allows to configure OWE transition VAPs without adding SSID / BSSID
to the uci conifg but instead autodiscovering these parameters from
other networks on the same PHY.

The following configuration creates a OWE transition mode network
constellation.

config wifi-iface 'open0'
	option device 'radio0'
	option ifname 'open0'
	option network 'lan'
	option mode 'ap'
	option ssid 'FreeNet'
	option encryption 'none'
	option owe_transition_ifname 'owe0'

config wifi-iface 'owe0'
	option device 'radio0'
	option ifname 'owe0'
	option network 'lan'
	option mode 'ap'
	option ssid 'owe_tm.FreeNet'
	option encryption 'owe'
	option hidden '1'
	option owe_transition_ifname 'open0'

Signed-off-by: David Bauer <mail@david-bauer.net>