[llvm] Improve how lowering of formal arguments in SPIR-V Backend interprets a value of 'kernel_arg_type' (PR #78730)

[Michal Paszkowski via llvm-commits]

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

Thank you for the pull request! Please rebase after PR #78603 is merged (EOD). Also, I would suggest moving the LIT test to `llvm/test/CodeGen/SPIRV/pointers` and using dashes in the name (instead of underscores, we are trying to move to one convention -- patch on the way :)). LGTM!

https://github.com/llvm/llvm-project/pull/78730