Speed up CDEF parameter selection for cpu-used > 0

High delay cpu-used=4
   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |    SSIM | MS SSIM | CIEDE 2000
 0.0579 |  0.1380 | -0.1975 |   0.0361 |  0.0226 |  0.0072 |     0.0470

Low delay cpu-used=4
   PSNR | PSNR Cb | PSNR Cr | PSNR HVS |    SSIM | MS SSIM | CIEDE 2000
-0.1016 | -0.0695 |  0.1013 |  -0.1324 | -0.0903 | -0.1260 |    -0.1710

Change-Id: I5a66a1ffc2d1fb2a203065b7fbb2fd2bd2b281ad
3 files changed