ggml-cpu: add RVV repack GEMM and GEMV for quantization types (#19121)
* ggml-cpu: add rvv ggml_quantize_mat_4x8 for q8_0
Co-authored-by: Rehan Qasim <rehan.qasim@10xengineers.ai>
* ggml-cpu: add rvv repacking for iq4_nl
* ggml-cpu: add generic impl for iq4_nl gemm/gemv
* ggml-cpu: add rvv repacking for q8_0
* ggml-cpu: refactor; add rvv repacking for q4_0, q4_K
* ggml-cpu: refactor; add rvv repacking for q2_K
Co-authored-by: Rehan Qasim <rehan.qasim@10xengineers.ai>
* ggml-cpu: refactor rvv repack
---------
Co-authored-by: Rehan Qasim <rehan.qasim@10xengineers.ai>