Use OD_DIVU for small divisions in temporal_filter.

Replaces an approximate unsigned integer division with the bit exact
 OD_ILOG() implementation.
Removes the need to call vp10_temporal_filter_init() before calling
 vp10_temporal_filter_apply_c() by using a static table of constants.

ntt-short-1:

          MEDIUM (%) HIGH (%)
    PSNR -0.023045   0.115705
 PSNRHVS  0.023327   0.110230
    SSIM -0.039964   0.083594
FASTSSIM  0.037416  -0.100936

subset1:

         RATE (%) DSNR (dB)
    PSNR 0.00000  0.00000
 PSNRHVS 0.00000  0.00000
    SSIM 0.00000  0.00000
FASTSSIM 0.00000  0.00000

Change-Id: I97c5817463fcd8cb557c403a143b9cfaee4f102c