Update the DPAS layout documents and code for the latest OCL DPAS interface.

[chengjunlu]

The DPAS layout related code and documents were added based on the legacy GenISA DPAS interface which has been out of date.

Need to update the documents and the code corresponding to the latest implementation with OCL interface.

The documents:

intel-xpu-backend-for-triton/third_party/intel/include/Dialect/TritonIntelGPU/IR/TritonIntelGPUAttrDefs.td

Line 36 in 6db3b52

t0 ... t0 t1 ... t1 t2 ... t2 t3 ... t3 t4 ... t4 t5 ... t5 t6 ... t6 t7 ... t7 ^

The code for LinearLayout of DPAS.

intel-xpu-backend-for-triton/third_party/intel/lib/Dialect/TritonIntelGPU/IR/LinearLayoutConversions.cpp

Line 347 in 6db3b52

// For A operand: