Fix cuda adapter ref count.

Author: aarongreig

unified-runtime/source/adapters/cuda/adapter.hpp

@@ -20,10 +20,8 @@
 #include <memory>
 #include <mutex>
 
-struct ur_platform_handle_t_;
-
 struct ur_adapter_handle_t_ {
-  std::atomic<uint32_t> RefCount = 0;
+  std::atomic<uint32_t> RefCount = 1;
   std::mutex Mutex;
   struct cuda_tracing_context_t_ *TracingCtx = nullptr;
   logger::Logger &logger;