The value predicted using CfL is clipped to avoid going out of the
scope of the uint8. Both overflow and underflow was detected over
Subtset1.

Results on Subset1 (compared to 7e55571e with CfL enabled)

  PSNR | PSNR Cb | PSNR Cr | PSNR HVS |   SSIM | MS SSIM | CIEDE 2000
0.0019 |  0.0001 |  0.0009 |   0.0047 | 0.0020 |  0.0023 |     0.0012

Change-Id: Ie1190e2286aa90542eaa68b814cc5cfa031acb73