Add DTD files for M82_1G and M82_2G boards, also known as MXIII

These S802 boards come in 2 flavours:
- 1G RAM, 8G NAND, RTL8188
- 2G RAM, 8G NAND, AP6210

They were extracted from the firmwares at http://www.bee-link.com/en/article.php?id=134

Thank you for your great work.