[AMDGPU] Add 32-bit lo/hi got and pc relative variant kinds and emit appropriate relocations

Differential Revision: https://reviews.llvm.org/D25548


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284195 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed