[llvm] [mlir] [mlir][spirv] Fix int type declaration duplication when serializing (PR #145687)

[Jakub Kuderski via llvm-commits]

kuhar wrote:

@davidegrohmann We typically tag PRs like this with `Reland "..."` in the PR title and include information about what commits this relands and with what changes compared to the original. This way it's easier to trace things back to the very original PRs and understand what was broken and how it got fixed.

https://github.com/llvm/llvm-project/pull/145687