ggml : vector length agnostic SVE support (llama/9290)

ggml : vector length agnostic SVE support (llama/9290)

* Implemented vector length agnostic SVE using switch case for 512-bit, 256-bit, 128-bit vector lengths

* Implemented vector length agnostic SVE using switch case for 512-bit, 256-bit, 128-bit vector lengths

* Removed WhiteSpaces

* ggml : style changes + fix 512-bit nb loop check

- fix local scope in switch cases
- consistent predicate names
- empty lines when necessary
- opening braces, spaces
- const-correctness
- add asserts

* Update ggml/src/ggml-quants.c

Co-authored-by: Georgi Gerganov <redacted>
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Co-authored-by: Georgi Gerganov <redacted>