Fix/Raw acceleration data

[DavidM42]

Firstly all credit goes to @Paulolrl

I did not write the code for this. I just saw the comment from Paulo on a issue I was a part of, tested it in my own fork and did not find a PR for it yet. It works for me and others who tested it Patch is from https://github.com/creotiv/MiBand2/issues/5#issuecomment-673814033