wifi-scripts: ucode: fix unencrypted sta connection

add missing key_mgmt option

Fixes: https://github.com/openwrt/openwrt/issues/17578
Signed-off-by: Felix Fietkau <[email protected]>

package/network/config/wifi-scripts/files-ucode/usr/share/ucode/wifi/supplicant.uc

@@ -159,6 +159,8 @@ function setup_sta(data, config) {
 		config.group = 'GCMP';
 	}
 
+	config.key_mgmt ??= 'NONE';
+
 	config.basic_rate = ratelist(config.basic_rate);
 	config.mcast_rate = ratestr(config.mcast_rate);