MXFP4 Cast Transpose Triton [WIP]

[sarthak-amd]

Description

Implements the MXFP4 rowwise and columnwise FP32/BF16 -> MXFP4 fused quantization + cast kernel

• Verify Tolerances and functional Unit Tests

• The triton te_cast_transpose_mxfp4_triton currently outputs FP4 data in linear layout [M, N/2] with contiguous byte packing. AITER's gemm_a4w4 requires the B matrix in MFMA shuffle layout for tensor cores. This layout shuffle can be fused into the triton kernel in future.