Tiny remove duplicated code (#11164)

python/sglang/srt/utils.py

@@ -2618,14 +2618,6 @@ def read_system_prompt_from_file(model_name: str) -> str:
         return ""
 
 
-def bind_or_assign(target, source):
-    if target is not None:
-        target.copy_(source)
-        return target
-    else:
-        return source
-
-
 def prepack_weight_if_needed(weight):
     if weight.device != torch.device("cpu"):
         return weight