[llvm] [RISCV][Zicfilp] Enable Zicfilp CFI compiler behaviors by looking at module flags (PR #152121)

[Sam Elliott via llvm-commits]

lenary wrote:

As soon as you have module flags, you need to ensure that when LTO merges two modules, that you get the right errors or merge behaviour.

I understand that, unlike subtarget features, when linking all modules (and functions inside that module) need the same protection configuration, right? This semantic is probably the easiest to implement.

Please write a test for this and put it in `llvm/test/LTO/RISCV`

https://github.com/llvm/llvm-project/pull/152121