GPU Calc: Avoid dereferencing null 'score' field in some cases.

Change-Id: I2e76d19986326b15c088e6dcce1da3be3924d0fc
diff --git a/sc/source/core/opencl/opencl_device.cxx b/sc/source/core/opencl/opencl_device.cxx
index a3fa004..80062c6 100644
--- a/sc/source/core/opencl/opencl_device.cxx
+++ b/sc/source/core/opencl/opencl_device.cxx
@@ -391,19 +391,26 @@ ds_status pickBestDevice(ds_profile* profile, int* bestDeviceIdx)

    for (unsigned int d = 0; d < profile->numDevices; d++)
    {
        ds_device device =  profile->devices[d];
        LibreOfficeDeviceScore score = *(LibreOfficeDeviceScore*)device.score;
        ds_device device = profile->devices[d];
        LibreOfficeDeviceScore *pScore = (LibreOfficeDeviceScore*)device.score;

        float fScore = -1;
        if (pScore)
            fScore = pScore->fTime;
        else
            LOG_PRINTF("Unusual null score");

        if (DS_DEVICE_OPENCL_DEVICE == device.type)
        {
            LOG_PRINTF("[DS] Device[" << d << "] " << device.oclDeviceName << " (OpenCL) score is " << score.fTime);
            LOG_PRINTF("[DS] Device[" << d << "] " << device.oclDeviceName << " (OpenCL) score is " << fScore);
        }
        else
        {
            LOG_PRINTF("[DS] Device[" << d << "] CPU (Native) score is " << score.fTime);
            LOG_PRINTF("[DS] Device[" << d << "] CPU (Native) score is " << fScore);
        }
        if (score.fTime < bestScore)
        if (fScore < bestScore)
        {
            bestScore = score.fTime;
            bestScore = fScore;
            *bestDeviceIdx = d;
        }
    }