[llvm] [NVPTX] Add patterns for fma.relu.{f16|f16x2|bf16|bf16x2} (PR #114977)

[Fraser Cormack via llvm-commits]

https://github.com/frasercrmck commented:

The PR description needs updating to reflect some of the new changes - the conditions under which the optimization is legal/performed, and that some instructions are being removed.

https://github.com/llvm/llvm-project/pull/114977