Trivial: Remove duplicate EOF trailing newlines

[MaEtUgR]

Describe problem solved by this pull request
When merging master into a branch the and experiencing conflicts the merge can be completed after resolving the conflicts using git commit but with the currently existing EOF trailing newlines you get a bunch of messages like path/filename:linenumber: new blank line at EOF and it doesn't continue.

Describe your solution
Since these newlines are useless anyways I suggest to just remove them.

Test data / coverage
It's a trivial change and still compiles.

Additional context
I'm still following up to create usefull prs out of #12072 and using the oportunity to learn merging correctly since I have to still keep it up to date to take over missing things.

[bkueng]

Can you remore https://github.com/PX4/Firmware/blob/master/Tools/astyle/pre-commit#L50? I don't think it's required, since we have astyle, and it is the cause of such issues.

[MaEtUgR]

I don't think it's required, since we have astyle, and it is the cause of such issues.

But astyle doesn't get applied to CMake, Python, ... files and then we would suddenly have trailing whitespaces everywhere again not?

EDIT: But it should write why it fails.

[bkueng]

But astyle doesn't get applied to CMake, Python, ... files and then we would suddenly have trailing whitespaces everywhere again not?

Yeah that's a good point. But we would have that problem already since not everyone uses the pre-commit hook and it does not run on CI either. So I don't think it would make things worse.
If we want it, we should add it to CI as well.
Either way works for me.