ggml : fix loongson compile warnings (#7537)
* ggml : fix loongson compile warnings
ggml-ci
* Fix loongarch quantize test fail.
Fix unexpected error introduced during rebase code.
* tests : disable json test due to lack of python on the CI node
ggml-ci
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Co-authored-by: junchao-loongson <zhaojunchao@loongson.cn>
