[libc] [llvm] [libc][math] Refactor ilogbf implementation to header-only in src/__support/math folder. (PR #175522)

[Muhammad Bassiouni via llvm-commits]

https://github.com/bassiounix requested changes to this pull request.

Thank you for your PR, you are on the right track with some nit.

https://github.com/llvm/llvm-project/pull/175522