metal : improve FA + improve MoE (llama/12612)

metal : improve FA + improve MoE (llama/12612)

* ggml : FA with different K, V head sizes (CPU)

ggml-ci

* metal : add FA with HS=192

* metal : extend FA to support different K and V head sizes

ggml-ci

* metal : add FA vector kernels for heads K 192 and V 128

ggml-ci

* ggml : restrict op on other backends to equal head sizes

ggml-ci

* metal : optimize FA-vec kernel

ggml-ci

* metal : FA remove mq registers

* metal : improve MoE mul_mat_id condition

ggml-ci

* metal : fix comments + remove unnecessary addition

ggml-ci

* metal : avoid too much shared memory usage with mul_mat_id

ggml-ci