stty: Fix incorrect ppc64el type presumption

[BAMF0]

This pull request will make the function print_terminal_size assume that speed is of type u32 on PowerPC64 systems using little-endian. Additionally, it will structure the cfg attributes to separate target_os from target_arch for clarity.

Fixes #11282

[BAMF0]

It seems that the formatter does not agree with my choice of structuring the attributes, let me fix that.

[xtqqczze]

@BAMF0 Do tests pass on a powerpc64le target, I don't think we have coverage in CI.

[github-actions]

GNU testsuite comparison:

Skipping an intermittent issue tests/tty/tty-eof (passes in this run but fails in the 'main' branch)
Note: The gnu test tests/csplit/csplit-heap is now being skipped but was previously passing.
Note: The gnu test tests/seq/seq-epipe is now being skipped but was previously passing.
Congrats! The gnu test tests/cut/cut-huge-range is now passing!

[sylvestre]

Merci