Changing the weights of the first CRF filter in deringing

The old taps were equivalent to [2 2 3 2 3 2 2], while the new taps are
equivalent to [1 2 3 4 3 2 1]. The new coefficients improve metrics
slightly (not clear why).

ntt-short1 results:
          LOW (%)  MEDIUM (%) HIGH (%)
    PSNR NaN -0.126426 -0.209062
 PSNRHVS NaN 0.043873 -0.038114
    SSIM NaN -0.054293 -0.138431
FASTSSIM NaN -0.143498 0.245350

Change-Id: Iecadda68a4e9b33a49a807faf0a7dee6c9a119cb