ggml-cpu: support K tails in power10 Q8/Q4 MMA matmul (#24753)
* ggml-cpu: support K tails in Power10 MMA Q8/Q4 matmul
This patch removes the requirement that K be divisible by kc in the tinyBlas_Q0_PPC tiled matmul path. Process the final K panel using its actual depth and pass the reduced panel size through packing and kernel execution. This allows more workloads to use the MMA kernel and reduces fallback to mnpack.
* Apply suggestion from @taronaeo
Co-authored-by: Aaron Teo <taronaeo@gmail.com>
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Co-authored-by: Aaron Teo <taronaeo@gmail.com>