[clang] [AMDGPU] Stop coercing structs with FP and int fields to integer arrays (PR #185083)

[Matt Arsenault via cfe-commits]

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

LGTM, but I think the bitfield logic could use another round. Are we not packing if the bitfield happens to go over i32?

https://github.com/llvm/llvm-project/pull/185083