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

[Alex MacLean via llvm-commits]

https://github.com/AlexMaclean approved this pull request.

This looks reasonable to me, although I have not had a chance to dig into the issue this is trying to address very deeply. Please wait for @Artem-B to take a look as well.

P.S. I wonder if we should consider just making v2i64 a legal type. 

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