Adding Gemma 2 2B configs (#8784)

* Adding Gemma 2 2B configs

Updates to Q scaling and Gemma 2 model sizes to match v2 2B model.

* Update src/llama.cpp

Co-authored-by: slaren <slarengh@gmail.com>

---------

Co-authored-by: slaren <slarengh@gmail.com>

Author: pculliton

src/llama.cpp

@@ -4969,6 +4969,7 @@ static void llm_load_hparams(
                 hparams.attn_soft_cap = true;
 
                 switch (hparams.n_layer) {
+                    case 26: model.type = e_model::MODEL_2B; break;
                     case 42: model.type = e_model::MODEL_9B; break;
                     case 46: model.type = e_model::MODEL_27B; break;
                     default: model.type = e_model::MODEL_UNKNOWN;
@@ -11736,6 +11737,7 @@ struct llm_build_context {
 
                 // ref: https://github.com/google/gemma_pytorch/commit/03e657582d17cb5a8617ebf333c1c16f3694670e
                 switch (model.type) {
+                    case e_model::MODEL_2B:
                     case e_model::MODEL_9B:  Qcur = ggml_scale(ctx0, Qcur, 1.0f / sqrtf(float(n_embd_head_k)));   break;
                     case e_model::MODEL_27B: Qcur = ggml_scale(ctx0, Qcur, 1.0f / sqrtf(float(n_embd / n_head))); break;
                     default: GGML_ABORT("fatal error");