Add more comments to the members of CoreTLSData related to OpenCL.

modules/core/src/precomp.hpp

@@ -272,8 +272,8 @@ struct CoreTLSData
 
     RNG rng;
 //#ifdef HAVE_OPENCL
-    int device;
-    ocl::Queue oclQueue;
+    int device; // device index of an array of devices in a context, see also Device::getDefault
+    ocl::Queue oclQueue; // the queue used for running a kernel, see also getQueue, Kernel::run
     int useOpenCL; // 1 - use, 0 - do not use, -1 - auto/not initialized
 //#endif
     int useIPP; // 1 - use, 0 - do not use, -1 - auto/not initialized