Merge pull request #10143 from pengli:ocl4dnn

diff --cc modules/dnn/include/opencv2/dnn/dnn.hpp
Simple merge

diff --cc modules/dnn/src/dnn.cpp
Simple merge

diff --cc modules/dnn/src/ocl4dnn/src/ocl4dnn_conv_spatial.cpp
Simple merge

diff --cc modules/dnn/src/opencl/conv_layer_spatial.cl
Simple merge