Refactor: Remove len from add_ref_mv_candidate
Refactor: Remove len from add_ref_mv_candidate

This makes the interface of add_ref_mv_candidate clearer.

Change-Id: Ib2dd376af6e996515822272929f22b60e519f466

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