nvidia-gpu: deferred init for NvidiaGpuDevice

Adds deferred init for NvidiaGpuDevice, so that when we bind
to this, the this pointer is valid, i.e. after construction
is completed

Change-Id: I24a53d2ab9be1a2a4431368414a154b48347d2a2
Signed-off-by: Marc Olberding <molberding@nvidia.com>
diff --git a/src/nvidia-gpu/Inventory.cpp b/src/nvidia-gpu/Inventory.cpp
index 0541d81..6796a32 100644
--- a/src/nvidia-gpu/Inventory.cpp
+++ b/src/nvidia-gpu/Inventory.cpp
@@ -72,7 +72,10 @@
         acceleratorInterface->register_property("Type", std::string("GPU"));
         acceleratorInterface->initialize();
     }
+}
 
+void Inventory::init()
+{
     processNextProperty();
 }