[clang] [llvm] [mlir] [AMDGPU] add clamp immediate operand to WMMA iu8 intrinsic (PR #171069)

[Matt Arsenault via cfe-commits]

https://github.com/arsenm commented:

This can't just break existing uses. Needs to implement bitcode autoupgrade, and some compatibility on the builtin signature. 

Also, can we just infer clamping as an optimization fold based on the use context? 

https://github.com/llvm/llvm-project/pull/171069