[llvm] [AMDGPU] Add missing GFX10 buffer format d16 hi instructions (PR #84809)

[Joe Nash via llvm-commits]

https://github.com/Sisyph commented:

Why were these initially disabled? The origin commit review is not informative. Can you please add a codegen test to make sure they work? 

https://github.com/llvm/llvm-project/pull/84809