Re-allow 32x32 inter idtx.
Re-allow 32x32 inter idtx.

BUG=aomedia:1293

Change-Id: Iabdeb4ef7a98b034a4777527f727231f7b8815ee

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