[llvm] [AMDGPU] Provide default value in get intrinsic param type (PR #122448)

[Jakub Chlanda via llvm-commits]

jchlanda wrote:

This was flagged by a downstream static analysis tool.

The diff of [`getIntrinsicParamType`](https://github.com/llvm/llvm-project/pull/122448/files#diff-3c1a15c454360184b4858334b96dcf7f956a2b400afccaa359386a2a36bf88efR932) is slightly bigger, as it needed a clang format.

https://github.com/llvm/llvm-project/pull/122448