To spoof the mac address in these devices you can do as follows.
1.) Turn Off Wifi
2.) Use ES File Explorer or Root Explorer, Navigate to /data/etc/
Here you will find,
3.) Backup these files to your sdcard or any other location.
4.) Open sdcard/backups/wlan_macaddr0, edit in ES File Editor or any other text editing tool.
You will find your original mac address, change it to desired mac such as "00:11:22:33:44:55" and save it.
5.) Replace with original file.
6.) Turn on Wifi, check mac address in "About Phone".
Note: Other files wlan_macaddr1, wlan_macaddr2, wlan_macaddr3 are same as the wlan_macaddr0, just changing the first file does the job. If you want you can modify the other files too.
Mac Address will revert back to your original if you restart your phone.