vulkan: don't use seqno if ProcessResources is not found

On guest thread initialization, RenderThread may receive packets before
PUID is set. e.g. feature querying commands. And that's valid.

Change-Id: I068dba9355799ed06ccdbc09f06748c50c63d4d3
diff --git a/stream-servers/RenderThread.cpp b/stream-servers/RenderThread.cpp
index bc3090a..94d9c2d 100644
--- a/stream-servers/RenderThread.cpp
+++ b/stream-servers/RenderThread.cpp
@@ -457,10 +457,17 @@
                     .healthMonitor = &FrameBuffer::getFB()->getHealthMonitor(),
                     .metricsLogger = &metricsLogger,
                 };
+                uint32_t* seqno = nullptr;
+                if (processResources) {
+                    seqno = processResources->getSequenceNumberPtr();
+                }
                 last = tInfo.m_vkInfo->m_vkDec.decode(readBuf.buf(), readBuf.validData(), ioStream,
-                                                      processResources->getSequenceNumberPtr(),
-                                                      context);
+                                                      seqno, context);
                 if (last > 0) {
+                    if (!processResources) {
+                        ERR("Processed some Vulkan packets without process resources created. "
+                            "That's problematic.");
+                    }
                     readBuf.consume(last);
                     progress = true;
                 }