Remove prev_frame_mvs from setup_ref_mv_list()
Remove prev_frame_mvs from setup_ref_mv_list()

Removed prev_frame_mvs from setup_ref_mv_list() since it is not used
anymore.

Change-Id: Ib24a794c2ab6152843b64370f1658fe491e37549

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