Adding support for the Banana Pi M2 Ultra

Hi everyone,

I own this device, the Banana Pi M2 Ultra, and I want to add support upstream in OpenWrt.

The performance is much better than the already supported Banana Pi (Allwinner A20) which can only NAT around 400MBit/s. Since my internet is 600MBit/s, I wanted something faster, and the Banana Pi M2 Ultra with 4xCortex A7 is able to NAT at the full speed of my connection (600MBit).

I added a page on the Wiki ToH with the techdata.

Here is my GitHub PR to add support. I am already running OpenWrt trunk on my Banana Pi M2 Ultra.

While this is not the newest hardware, hopefully it is interesting to someone!

Regarding your PR:

From: https://openwrt.org/submitting-patches

If you add support for new hardware: Include in your commit message a short description of the hardware and how to install OpenWrt on it. Have a look at the recent additions for some examples