Fix Ctx Dev pointer for KUNLUN (#48184)

paddle/fluid/distributed/collective/ProcessGroupBKCL.cc

@@ -292,14 +292,14 @@ phi::DeviceContext* ProcessGroupBKCL::GetDeviceContext(
   const std::string& key = GetKeyFromPlace(place);
   if (use_calc_stream) {
     const auto& iter = place_to_calc_ctx_.find(key);
-    return *iter->second;
+    return iter->second;
   } else {
     const auto& iter = place_to_comm_ctx_.find(key);
     PADDLE_ENFORCE_NE(iter,
                       place_to_comm_ctx_.end(),
                       platform::errors::InvalidArgument(
                           "Cannot find device context in process group."));
-    return *iter->second;
+    return iter->second.get();
   }
 }