hostapd: introduce background_radar option
Introduce a new option background_radar to toggle hostapd's background radar feature. Enabling this allows DFS CAC to run on dedicated radio RF chains while the radio(s) are otherwise running normal AP activities on other channels.
As OpenWrt configures hostapd to use a channel list even when a single channel is configured, using this feature requires a list of channels in /etc/config/wireless. Alternatively, channel can be set to auto.
Signed-off-by: Stijn Tintel stijn@linux-ipv6.be Acked-by: David Bauer mail@david-bauer.net