AMDGPU: Respect align argument parameter

This should avoid relying on the pointee type
to get the alignment, particularly since pointee
types are supposed to be removed at some point.

Also fixes not getting the alignment for unsized types.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@335478 91177308-0d34-0410-b5e6-96231b3b80d8
3 files changed