[llvm] [AMDGPU][True16] set true16 mode as default on gfx110x (PR #140736)

[Joe Nash via llvm-commits]

Sisyph wrote:

> What's the reason for restricting it to gfx110x? Are you just being cautious? Or are there known problems with gfx115x and gfx12?

There are known issues on both those subtargets.
For GFX115x, this is the only known issue. https://github.com/llvm/llvm-project/pull/138734
For GFX12, there are several things to implement, and it has not been tested yet.

https://github.com/llvm/llvm-project/pull/140736