fix build target dependencies in opencl backend
fix build target dependencies in opencl backend

arrayfire/arrayfire,umar456/arrayfire,munnybearz/arrayfire,umar456/arrayfire,9prady9/arrayfire,munnybearz/arrayfire,umar456/arrayfire,9prady9/arrayfire,umar456/arrayfire,arrayfire/arrayfire,arrayfire/arrayfire,9prady9/arrayfire,munnybearz/arrayfire,9prady9/arrayfire,arrayfire/arrayfire