[CI][AMD]Bugfix] Check that model_config is not None in enable_norm_pad_fusion (#34007)

Signed-off-by: Randall Smith <Randall.Smith@amd.com>

vllm/config/vllm.py

@@ -109,6 +109,7 @@ def enable_norm_pad_fusion(cfg: "VllmConfig") -> bool:
         envs.VLLM_ROCM_USE_AITER
         and envs.VLLM_ROCM_USE_AITER_RMSNORM
         and envs.VLLM_ROCM_USE_AITER_TRITON_GEMM
+        and cfg.model_config is not None
         and cfg.model_config.get_hidden_size() == 2880
     )