[llvm] [AMDGPU][True16] Legalize S16 for G_STORE/G_LOAD in GlobalISel when True16 is enabled (PR #176963)

[Petar Avramovic via llvm-commits]

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

LGTM overall, but still need to re-check in a few places

https://github.com/llvm/llvm-project/pull/176963