LA915 region not supported

[anacforcelli]

I am working from Brazil and have been struggling for a while to make my company's custom board work on our LoRaWAN network (hosted by American Tower).

Recently I found out that the AU915 localization, whilst similar to LA915 specification, does not work seamlessly and there is a lot of packet loss that may be due to different RX/TX window differences.

I am attempting to change the parameters as of now and may report later today. If successful, a PR will be submitted. Otherwise, I will return for help.

Thanks in advance!