[llvm] [NVPTX] pull in v2i32 build_vector through v2f32 bitcast (PR #153478)

[Princeton Ferro via llvm-commits]

Prince781 wrote:

@AlexMaclean 
> P.S. I wonder if we should consider just making v2i32 a legal type.

I thought about this as well. I'm hesitant to introduce another legal type and plumb it through NVPTX (although it should be far less effort than v2f32) when there aren't any instructions that support v2i32. If we see more bug reports related to this issue then I'll reconsider it.

https://github.com/llvm/llvm-project/pull/153478