File to add OpenCL lib about armnn

[MatthewARM]

Hi @phamyphen some people have reported that issue before, we don't have a good fix for it yet but there is a workaround, I'll dig it out...

[MatthewARM]

@phamyphen please try removing line 271 of cmake/GlobalConfig.cmake, which should say:
find_library(OPENCL_LIBRARIES OpenCL)

Then delete your build directory and re-run cmake.

This will stop it from ever finding the host system OpenCL library.

[phamyphen]

Thanks MatthewARM.
The problem is solved based on your solution.