[mlir][vector][spirv] Add SPIR-V lowering for `vector.to_elements`

[dcaballe]

Similar to the lowering to LLVM, we need to add the corresponding lowering to SPIR-V for vector.to_elements.

[llvmbot]

@llvm/issue-subscribers-mlir

Author: Diego Caballero (dcaballe)

Similar to the [lowering to LLVM](https://github.com//pull/145766), we need to add the corresponding lowering to SPIR-V for `vector.to_elements`.

[llvmbot]

@llvm/issue-subscribers-mlir-spirv

Author: Diego Caballero (dcaballe)

Similar to the [lowering to LLVM](https://github.com//pull/145766), we need to add the corresponding lowering to SPIR-V for `vector.to_elements`.

[kuhar]

The conversion pattern should be added to

llvm-project/mlir/lib/Conversion/VectorToSPIRV/VectorToSPIRV.cpp

Line 1023 in a68e447

};

The tests are in https://github.com/llvm/llvm-project/blob/main/mlir/test/Conversion/VectorToSPIRV/vector-to-spirv.mlir