IPQ4019: Adding support for TP-Link Deco M9 Plus

There's a single mention of Deco M9 in the thread for Deco M5, but no followup. I have five M9s (v1) that I'm starting to feel I need to either switch out or get supported third party firmware onto. I've looked quickly at the hardware similarities between the M5 and M9, and it seems they are very similar. The M9 is of course tri-band, which improves the wireless mesh throughput.

http://en.techinfodepot.shoutwiki.com/wiki/TP-LINK_Deco_M5

If someone has already worked on this, it would be good to know. Otherwise I will start looking into it now. The extra features of the M9 Plus (Zigbee .. ) are less interesting for me, unless it would be possible to just make them standard repeaters (which the TP-Link fw does not do).