[llvm] [SPIR-V] Fix legalize info for G_BITREVERSE (PR #93699)

[Vyacheslav Levytskyy via llvm-commits]

VyacheslavLevytskyy wrote:

> I think HLSL should have a `reversebits` test that might be affected by this change, can you confirm?

@farzonl I don't expect HLSL's `reversebits` test to be affected, as it uses i16 and i32 for bitreverse. This PR is a start of fixing the issue with llvm.bitreverse applied to other than 8,16,32,64 integer sizes.

https://github.com/llvm/llvm-project/pull/93699