model : fix Granite Hybrid type check for 7B.A1B (ggml-org#20795)

* Check granite hybriid expert count to set type as LLM_TYPE_7B_A1B or LLM_TYPE_1B

* Use feed fwd dim instead of num of experts

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

---------

Co-authored-by: Sigbjørn Skjæret <sigbjorn.skjaeret@scala.com>

Author: 2 people

src/llama-model.cpp

@@ -2058,7 +2058,7 @@ void llama_model::load_hparams(llama_model_loader & ml) {
 
                 switch (hparams.n_embd) {
                     case 768: type = LLM_TYPE_350M; break;
-                    case 1536: type = (hparams.n_embd == 2048 ? LLM_TYPE_7B_A1B : LLM_TYPE_1B); break;
+                    case 1536: type = (hparams.n_ff() == 512 ? LLM_TYPE_7B_A1B : LLM_TYPE_1B); break;
                     case 2048: case 2560: type = LLM_TYPE_3B; break;
                     case 4096: type = LLM_TYPE_32B; break;
                     default: type = LLM_TYPE_UNKNOWN;