mac80211: add support for specifying a per-device scan list

This is useful to bring up multiple client mode interfaces on a single
channel much faster without having to scan through a lot of channels

Signed-off-by: Felix Fietkau <nbd@nbd.name>

package/network/services/hostapd/files/hostapd.sh

@@ -896,6 +896,7 @@ wpa_supplicant_prepare_interface() {
 	fi
 	wpa_supplicant_teardown_interface "$ifname"
 	cat > "$_config" <<EOF
+${scan_list:+freq_list=$scan_list}
 $ap_scan
 $country_str
 EOF