[llvm] [NFC][LLVM] Remove unused `TargetIntrinsicInfo` class (PR #126003)

[Rahul Joshi via llvm-commits]

jurahul wrote:

> > Can we remove this immediately or do we need to deprecate it for a release cycle? Either way it needs to be documented in the llvm Release Notes
> 
> I am not sure if there are any downstream users. I'll update release notes and post on the forum as well. @nikic is that sufficient, or should we follow more rigor here (i.e, deprecate it in some way) and delete in later?

I started https://discourse.llvm.org/t/removing-targetintrinsicinfo-support/84470

https://github.com/llvm/llvm-project/pull/126003