wifi-scripts: add free-form "tags" array option for wifi-iface

This allows annotating wifi interfaces in the config in a way that can be
queried through wifi status. One example use case is to mark wifi interfaces
for use with specific services without having to explicitly reference the
(often unnamed) sections from elsewhere.

Signed-off-by: Felix Fietkau <[email protected]>
(cherry picked from commit a3ec35cadb77265c0e00c8d3789734586a6f7111)

package/network/config/wifi-scripts/files/lib/netifd/netifd-wireless.sh

@@ -379,6 +379,7 @@ _wdev_common_device_config() {
 _wdev_common_iface_config() {
 	config_add_string mode ssid encryption 'key:wpakey'
 	config_add_boolean bridge_isolate
+	config_add_array tags
 }
 
 _wdev_common_vlan_config() {