[MLIR][XeGPU] Add XeGPU scattered ops (#86594)

- Extended TensorDescAttr with scattered attribute
- Add scattered ops: CreateDescOp, PrefetchOp, LoadGatherOp,
StoreScatterOp, UpdateOffsetOp
- Add a block op: UpdateNdOffsetOp

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Co-authored-by: Mehdi Amini <joker.eph@gmail.com>
Co-authored-by: Adam Siemieniuk <adam.siemieniuk@intel.com>