doc: included OpenCL API extensions to reference manual

Author: vpirogov

doc/Doxyfile.in

@@ -1937,7 +1937,7 @@ INCLUDE_FILE_PATTERNS  =
 # recursively expanded use the := operator instead of the = operator.
 # This tag requires that the tag ENABLE_PREPROCESSING is set to YES.
 
-PREDEFINED             = DOXYGEN_SHOULD_SKIP_THIS
+PREDEFINED             = DOXYGEN_SHOULD_SKIP_THIS DNNL_GPU_RUNTIME=DNNL_RUNTIME_OCL
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this
 # tag can be used to specify a list of macro names that should be expanded. The