[bugfix] some bugs maybe fail to run (#896)

### What this PR does / why we need it?
Solve the bug that the graph mode is the same as p and d, and some other
bugs.
### Does this PR introduce _any_ user-facing change?
Wouldn't be
### How was this patch tested?
Follow the end-to-end test

Signed-off-by: ningbenzhe1 <ningbenzhe@huawei.com>

vllm_ascend/patch/platform/patch_common/patch_distributed.py

@@ -20,6 +20,7 @@
 import torch
 import vllm
 import vllm.distributed
+import vllm.envs as envs
 from torch.distributed import ProcessGroup
 from torch.distributed.distributed_c10d import (Backend, PrefixStore,
                                                 _get_default_timeout,
@@ -164,10 +165,9 @@ def parallel_config_get_dp_port(self) -> int:
     """
     answer = self.data_parallel_master_port
     self.data_parallel_master_port += 1
-    import os
 
     # NOTE: Get port from envs directly when using torchrun
-    port = int(os.environ.get("MASTER_PORT", answer))  # type: ignore
+    port = envs.VLLM_DP_MASTER_PORT if envs.VLLM_DP_MASTER_PORT else answer
     return port