Refactor modify_neighbor_predictor_for_obmc()
Refactor modify_neighbor_predictor_for_obmc()

Remove redundant logics

Change-Id: If8d329ca8b5e1dbbe018942c6ec12e4523e81682

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom