model : Port Minimax M2 from mainline

[firecoperana]

Add support for Minimax M2 ggml-org/llama.cpp#16831
Closes #877
Only add model support. Tool calling support is not yet merged.

[ikawrakow]

The code from here to line 8416 can now be replaced with

            auto [Qcur, Kcur, Vcur] = llm_build_mul_mat_qkv(gf, cur, 
                    model.layers[il].wqkv, nullptr, model.layers[il].wqk, nullptr,
                    model.layers[il].wq, nullptr, model.layers[il].wk, nullptr, model.layers[il].wv, nullptr,
                    model.layers[il].attn_q_norm, model.layers[il].attn_k_norm, 0, il); 

In that way we don't need to worry about how Q, K, V should be reshaped, we automatically get Q,K,V fusion for this model if the user requested via -mqkv, and we use a standardized way to compute attention (when attention is standard as it is here).

It would be useful to do that so it can get tested as part of this PR.

[firecoperana]

I get error ik_llama.cpp\ggml\src\ggml.c:6358: GGML_ASSERT(ggml_can_repeat(b, a)) failed when loading the model using cpu only backend after incorporating both changes. I think it's that the buffer of a is null that caused the crash.
Call Stack:

 	ggml.dll!ggml_abort(const char * file, int line, const char * fmt, ...) Line 272	C
 	ggml.dll!ggml_mul_impl(ggml_context * ctx, ggml_tensor * a, ggml_tensor * b, bool inplace) Line 6360	C
>	ggml.dll!ggml_fused_rms_norm_impl(ggml_context * ctx, ggml_tensor * a, ggml_tensor * b, float eps, bool inplace) Line 7277	C
 	ggml.dll!ggml_fused_rms_norm(ggml_context * ctx, ggml_tensor * a, ggml_tensor * b, float eps) Line 7305	C
 	llama.dll!llm_build_context::llm_build_norm(ggml_context * ctx, ggml_tensor * cur, const llama_hparams & hparams, ggml_tensor * mw, ggml_tensor * mb, llm_norm_type type, const std::function<void __cdecl(ggml_tensor *,char const *,int)> & cb, int il, float scale_eps) Line 582	C++
 	llama.dll!llm_build_context::llm_build_mul_mat_qkv(ggml_cgraph * gf, ggml_tensor * cur, ggml_tensor * wqkv, ggml_tensor * bqkv, ggml_tensor * wqk, ggml_tensor * bqk, ggml_tensor * wq, ggml_tensor * bq, ggml_tensor * wk, ggml_tensor * bk, ggml_tensor * wv, ggml_tensor * bv, ggml_tensor * q_norm, ggml_tensor * k_norm, float attention_scale, int il) Line 1348	C++
 	llama.dll!llm_build_context::build_minimaxm2() Line 8418	C++

[ikawrakow]

Oh, I see. The attn_q_norm and attn_k_norm tensors are not just 1d with the size of one attention head, but rather head_size x head_count, so the usual trick of fusing the RMS_NORM, does not work. Sorry. Ignore the two comments then.