[llvm] [AMDGPU] Suppress DataLayout warnings after recent change (PR #163644)

[Shilei Tian via llvm-commits]

shiltian wrote:

> because it is a legitimately different data layout with different semantics

This depends because in this particular case it doesn't _actually_ change anything, and this is also the whole point of IR upgrade.

I don't prefer to suppress any warning if it is not the only solution but I'm also open to other opinions.

https://github.com/llvm/llvm-project/pull/163644