CUDA: faster non-contiguous concat (#10760)
* faster uncontiguous concat
* Use a lambda to avoid code duplication
Co-authored-by: Diego Devesa <slarengh@gmail.com>
* Update ggml/src/ggml-cuda/concat.cu
* add constexpr and static assert
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Co-authored-by: Diego Devesa <slarengh@gmail.com>
