[MLIR][NVGPU] Introduction of wgmma.generate.descriptor Op

This work introduces a new Op, `wgmma.generate.descriptor`, designed to create a wgmma descriptor for inputs of matrix multiply and accumulate operations using `wgmma.mma_async` PTX instruction.

The descriptor format specifications can be found in the following link:
https://docs.nvidia.com/cuda/parallel-thread-execution/index.html#asynchronous-warpgroup-level-matrix-shared-memory-layout-matrix-descriptor

It's important to note that this op is in its initial phase, and it does come with certain limitations. It only supports 128b swizzling and does not incorporate interleaving. In the future, different calculations will be addressed in separate works, expanding the capabilities of the op.

Reviewed By: qcolombet

Differential Revision: https://reviews.llvm.org/D157382