Refactor av1_down_sample_scan_count
Refactor av1_down_sample_scan_count

Change-Id: I18de826d8b8bdec6f57d108906ee5df959243f90

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