Drop ascend scheduler (#4623)

It's safe to drop ascend scheduler now. The related test and doc has
been removed already


- vLLM version: v0.12.0
- vLLM main:
ad32e3e19c

Signed-off-by: wangxiyuan <wangxiyuan1007@gmail.com>

vllm_ascend/torchair/torchair_attention.py

@@ -451,8 +451,7 @@ class AscendAttentionTorchairBackendImpl(AttentionImpl):
         else:
             raise NotImplementedError(
                 "Torchair graph mode with non-MLA attention backend is still experimental."
-                "v1 scheduler(chunked prefill) is not supported at this moment. Please"
-                "setting 'ascend_scheduler_config':{'enabled':true} in additional_config"
-                "to use ascend scheduler.")
+                "v1 scheduler(chunked prefill) is not supported at this moment."
+            )
 
         return output.view(num_tokens, self.hidden_size)