Fix a typo.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198045 91177308-0d34-0410-b5e6-96231b3b80d8
TLI: Make exp10* avaiable on Linux/Mac/iOS and unavailable elsewhere

This makes it unavailable on NetBSD, Android, etc.

Patch by Brad Smith!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@198056 91177308-0d34-0410-b5e6-96231b3b80d8