Add Exaone4 AWQ mapping (#2046)

EXAONE4 uses
[QK-Reorder-Norm](https://huggingface.co/LGAI-EXAONE/EXAONE-4.0-32B#introduction).

Transformers:
[Exaone4DecoderLayer](https://github.com/huggingface/transformers/blob/v4.57.1/src/transformers/models/exaone4/modeling_exaone4.py#L284-L314)

```python
class Exaone4DecoderLayer(GradientCheckpointingLayer):
    def forward(
        self,
        hidden_states: torch.Tensor,
        attention_mask: Optional[torch.Tensor] = None,
        position_ids: Optional[torch.LongTensor] = None,
        past_key_values: Optional[Cache] = None,
        use_cache: Optional[bool] = False,
        cache_position: Optional[torch.LongTensor] = None,
        position_embeddings: Optional[tuple[torch.Tensor, torch.Tensor]] = None,
        **kwargs: Unpack[TransformersKwargs],
    ) -> torch.Tensor:
        residual = hidden_states
        hidden_states, _ = self.self_attn(
            hidden_states=hidden_states,
            attention_mask=attention_mask,
            position_ids=position_ids,
            past_key_values=past_key_values,
            use_cache=use_cache,
            cache_position=cache_position,
            position_embeddings=position_embeddings,
            **kwargs,
        )
        hidden_states = self.post_attention_layernorm(hidden_states)
        hidden_states = residual + hidden_states

        # Fully Connected
        residual = hidden_states
        hidden_states = self.mlp(hidden_states)
        hidden_states = self.post_feedforward_layernorm(hidden_states)
        hidden_states = residual + hidden_states
        return hidden_states
```

Signed-off-by: lkm2835 <lkm2835@gmail.com>

Author: lkm2835

src/llmcompressor/modifiers/awq/mappings.py

@@ -142,12 +142,23 @@ class AWQMapping:
     #     ["re:.*dense$"]
     # ),
 ]
+
+# Exaone4
+_exaone4_mappings = [
+    AWQMapping("re:.*v_proj$", ["re:.*o_proj$"]),
+    AWQMapping(
+        "re:.*up_proj$",
+        ["re:.*down_proj$"],
+    ),
+]
+
 AWQ_MAPPING_REGISTRY: dict[str, list[AWQMapping]] = {
     "BloomForCausalLM": _bloom_mappings,
     "CohereForCausalLM": _cohere_mappings,
     "Cohere2ForCausalLM": _cohere_mappings,
     "Cohere2VisionForConditionalGeneration": _cohere_mappings,
     "DeepseekV3ForCausalLM": _deepseek_mappings,
+    "Exaone4ForCausalLM": _exaone4_mappings,
     "Gemma2ForCausalLM": _gemma_mappings,
     "Gemma3ForCausalLM": _gemma_mappings,
     "Gemma3ForConditionalGeneration": _gemma_mappings,