ccl_kernel_suggest_worksizes: no need for gws%lws==0 for OpenCL >= 2.0

OpenCL 2.0 and higher do not require that global work size be a multiple of the local work size. Reflect this in the [ccl_kernel_suggest_worksizes](https://github.com/fakenmc/cf4ocl/blob/master/src/lib/ccl_kernel_wrapper.c#L903) function.