ggml-cuda: ds_read_b128 for q4_0 and q4_1 mmq kernels (llama/21168)

ggml-cuda: ds_read_b128 for q4_0 and q4_1 mmq kernels (llama/21168)

* ds_read_b128 for q4_0 and q4_1 mmq kernels

     Current for loop generates ds_read_b32 instructions with hip compiler, the new solution generates ds_read_b128 instructions for the same operation, saving some LDS bandwidth. Tested on MI50 and RX6800XT, its faster on both.

* Vectorized lds load update: used ggml_cuda_get_max_cpy_bytes and ggml_cuda_memcpy_1 functions for generic implementation

* Explicit for loop in mmq, renamed vec into tmp

* Fixed max_cpy usage in the loading loop

* Fixed typo in q4_1 kernel

* Update ggml/src/ggml-cuda/mmq.cuh

Co-authored-by: Johannes Gäßler <redacted>
* Update ggml/src/ggml-cuda/mmq.cuh

Co-authored-by: Johannes Gäßler <redacted>
* Update ggml/src/ggml-cuda/mmq.cuh

Co-authored-by: Johannes Gäßler <redacted>
* Renoved trailing white line 500

* Update mmq.cuh removed other whitelines

* Remove trailing whitespaces

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Co-authored-by: iacopPBK <redacted>
Co-authored-by: Johannes Gäßler <redacted>
Co-authored-by: iacopPBK <redacted>