[llvm] [AMDGPU] Fix kernarg preloading crash with some types and alignments (PR #91625)

[Austin Kerbow via llvm-commits]

kerbowa wrote:

> GlobalISel path probably needs equivalent fix? Was this implemented there?
Preloading isn't implemented in GlobalISel so the fix isn't needed there. It doesn't crash or anything if you try to use the preloading flag with gisel, but it wont actually do anything.

https://github.com/llvm/llvm-project/pull/91625