[Banana BPI-R4] all related to MTK-SDK

For those trying to test, there is a new version in the repo.

@woziwrt I haven’t had time to test this properly but so far so good. The WiFi range and stability seems to have improved based on the fact I currently have ~20 devices connected. I had to restart it a couple of times because the WiFi stoped working (even tho was broadcasting / I could see it in the list) but unclear why.