[llvm] [AMDGPU][GlobalISel] Add register bank legalization for G_AMDGPU_BUFFER_LOAD_BYTE_AND_SHORT (PR #167798)

[Petar Avramovic via llvm-commits]

https://github.com/petar-avramovic commented:

Need to add a few UniInVgpr tests (have load used by instruction that has salu version, for example add)

https://github.com/llvm/llvm-project/pull/167798