SWDEV-317253 - int underflow causes an assertion with no node in graph. This fixes it.

Change-Id: I9bc293866d69c803381762256ce31f3d80d2afda

hipamd/src/hip_graph_internal.cpp

@@ -665,7 +665,8 @@ hipError_t hipGraphExec::CreateQueues(size_t numQueues) {
 
 hipError_t hipGraphExec::Init() {
   hipError_t status;
-  size_t reqNumQueues = 0;
+  size_t reqNumQueues = 1;
+
   for (auto& node : levelOrder_) {
     reqNumQueues += node->GetNumParallelQueues();
   }