[llvm] [mlir] Add cond_sub and sub_clamp operations to atomicrmw (PR #96661)

[Thorsten Schütt via llvm-commits]

tschuett wrote:

Could you please extend 
https://github.com/llvm/llvm-project/blob/main/llvm/include/llvm/CodeGen/GlobalISel/MachineIRBuilder.h

Thanks.

https://github.com/llvm/llvm-project/pull/96661