[llvm] [AMDGPU] Do not use 64-bit literals with VOP3* encodings (PR #156602)

[Stanislav Mekhanoshin via llvm-commits]

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

LGTM, but I'd probably check Desc size directly instead of flags.

https://github.com/llvm/llvm-project/pull/156602