CL: Add support for atomic ops
This patchset plugs NIR atomic intrinsics to the DXIL atomic operations. As discussed previously, the situation is not ideal right now because SPIRVtoNir generates extra barriers around each atomic operations, which wouldn't be needed if we were passed the memory semantics along the atomic operation. This is being worked on here mesa/mesa!4917 (closed), but I thought it'd be good to still have support for atomic operations even if it's not optimal.