Makes second filters for 45-degree directions horizontal

This reduces the deringing worst-case number of "latency" lines from 10 to 8.

ntt-short1 results:
         MEDIUM (%) HIGH (%)
    PSNR -0.063681 -0.027661
 PSNRHVS -0.063628 -0.007841
    SSIM -0.007828 -0.048415
FASTSSIM  0.139420 -0.183910

Change-Id: I006544ab748b76c0334e406300b3eda20e125846