[MLIR][XeGPU] Add support for cross-subgroup reduction from wg to sg#170936

nbpatel wants to merge 2 commits intollvm:mainllvm/llvm-project:mainfrom

nbpatel:xegpu-wg-sg-reduction-cross-subgroupnbpatel/llvm-project:xegpu-wg-sg-reduction-cross-subgroupCopy head branch name to clipboard