Set up eob_ctx for TX64X64 properly
Set up eob_ctx for TX64X64 properly

BUG=aomedia:1096

Change-Id: Ibbb448e217ae1dd9a096c23d01b08c9804583003

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