* may be an typo fix
* remove identical branch,may be paste error
* add parentheses around macro parameter
* simplify if condition
* check malloc fail
* change the condition of branch removed by commit 3041502861318c85d901e8c08226ff67898c77ed
Add ocl version BackgroundSubtractorKNN (#10553)
* Add ocl version bgfg_knn
* Add ocl KNN perf test
* ocl KNN: Avoid unnecessary initializing when non-UMat parameters are used
* video: turn off OpenCL for color KNN on Intel devices
due performance degradation
* video: turn off KNN OpenCL on Apple devices with Intel iGPU
due process freeze during clBuildProgram() call
The method does cvCheckPixelBackgroundNP (which reads bgmodel)
before it is ever updated (in cvUpdatePixelBackgroundNP). This
initialization is thus needed to avoid reads of unitialized values.
