[llvm] [mlir] [mlir][x86vector] Simplify intrinsic generation (PR #133692)

[Andrzej Warzyński via llvm-commits]

https://github.com/banach-space commented:

Having less code to compile+maintain is always good, thanks! This makes sense to me. 

I've left some minor comments and have one higher level question - it looks like most/all LLVM intrinsic resolution takes place in `getIntrinsicName()` methods - am I correct? If "yes", then I guess the comment in `MaskCompressOp` needs updating?

https://github.com/llvm/llvm-project/pull/133692