SWDEV-450361 - Add nullptr validation for waitStream

- Application is passing null for parameter stream in API hipStreamWaitEvent
- When event stream isn't capturing and event is not recorded, causes segfault because we are accessing deviceId() from waitStream

Change-Id: I8b87ffd6f234677f68b66dcb7ef44b2ff04a7c91

hipamd/src/hip_stream.cpp

@@ -463,7 +463,7 @@ hipError_t hipStreamWaitEvent_common(hipStream_t stream, hipEvent_t event, unsig
         // If stream is capturing but event is not recorded on event's stream.
         return hipErrorStreamCaptureIsolation;
       }
-      if (eventStream->DeviceId() == waitStream->DeviceId()) {
+      if ((waitStream != nullptr) && (eventStream->DeviceId() == waitStream->DeviceId())) {
         eventStream->GetDevice()->AddSafeStream(eventStream, waitStream);
       }
     }