[clang] [FMV] Add "+fmv" to the target-features of versioned functions. (PR #116028)

[Alexandros Lamprineas via cfe-commits]

labrinea wrote:

This is an improvement over https://github.com/llvm/llvm-project/pull/87942 so that we don't optimize non FMV ifuncs as explained here https://github.com/llvm/llvm-project/pull/87939#issuecomment-2470557080

https://github.com/llvm/llvm-project/pull/116028