Loader: GPA fixes  and also properly insert wrapped gpu objs into chain

Loader wasn't properly inserting the wrapped gpu objects for activated layers
into  the chain of objects.  This was a problem for any calls that used
the wrapped gpu object chain after activation of layers.
diff --git a/loader/loader.h b/loader/loader.h
index 47802d4..e2c1ade 100644
--- a/loader/loader.h
+++ b/loader/loader.h
@@ -40,6 +40,6 @@
 #  define LOADER_EXPORT
 #endif
 
-extern XGL_UINT ActivateLayers(XGL_PHYSICAL_GPU *gpu, const XGL_DEVICE_CREATE_INFO* pCreateInfo);
+extern XGL_UINT ActivateLayers(XGL_PHYSICAL_GPU gpu, const XGL_DEVICE_CREATE_INFO* pCreateInfo);
 #define MAX_LAYER_LIBRARIES 64
 #endif /* LOADER_H */