2014-08-04  Sharath Kamath  <s.kamath@samsung.com>

        Enable the KHR_FP64 & KHR_FP16 extension.

        Issue #536 - [Part-1]

        Reviewed by Antonio.

        Pushing the extension availability to OpenCL, and enabling only when
        the OpenCL lists the extensions name "cl_khr_fp64" & "cl_khr_fp16" in the device & platform
        getInfo() calls.

        * platform/opencl/ComputeExtensionsCL.cpp:
        (WebCore::ComputeExtensions::supportsExtension):