* Fix a case where we would calculate the Y horizontal filter strength
  as the sum of the base Y *vertical* strength and the
  per-segment delta Y horizontal strength.

* When using delta_lf_multi, adapt the corresponding CDFs between frames

* Correct values in seg_feature_data_{signed,max}

Change-Id: I1976d2024e9e16fe73258cf41d56aafe8a830957