ggml: aarch64: Implement SVE F16 kernels for vector functions (#15115)
* Added sve implementation for vec_dot_fp16 Kernel
* removed white spaces
* Added comment
* removed white spaces
* changed GGML_F16x_VEC_FMA for code consistency
* Update vec.h
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Co-authored-by: vithulep <p.m.vithule1517@gmail.com>